It appears that in commit 9d7a224b46 ("dma-direct: always allow dma mask
<= physiscal memory size") the logic of the test was changed from a "<" to
a ">=" however I don't see any reason for that change. I am assuming that
there was some additional change planned, specifically I suspect the logic
was intended to be reversed and possibly used for a return. Since that is
the case I have gone ahead and done that.
This addresses issues I had on my system that prevented me from booting
with the above mentioned commit applied on an x86_64 system w/ Intel IOMMU.
Fixes: 9d7a224b46 ("dma-direct: always allow dma mask <= physiscal memory size")
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Architectures have extra archdata in the clocksource, e.g. for VDSO
support. There are no sanity checks or general initializations for this
available. Add support for that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130706.973042587@linutronix.de
A cgroup which is already a threaded domain may be converted into a
threaded cgroup if the prerequisite conditions are met. When this
happens, all threaded descendant should also have their ->dom_cgrp
updated to the new threaded domain cgroup. Unfortunately, this
propagation was missing leading to the following failure.
# cd /sys/fs/cgroup/unified
# cat cgroup.subtree_control # show that no controllers are enabled
# mkdir -p mycgrp/a/b/c
# echo threaded > mycgrp/a/b/cgroup.type
At this point, the hierarchy looks as follows:
mycgrp [d]
a [dt]
b [t]
c [inv]
Now let's make node "a" threaded (and thus "mycgrp" s made "domain threaded"):
# echo threaded > mycgrp/a/cgroup.type
By this point, we now have a hierarchy that looks as follows:
mycgrp [dt]
a [t]
b [t]
c [inv]
But, when we try to convert the node "c" from "domain invalid" to
"threaded", we get ENOTSUP on the write():
# echo threaded > mycgrp/a/b/c/cgroup.type
sh: echo: write error: Operation not supported
This patch fixes the problem by
* Moving the opencoded ->dom_cgrp save and restoration in
cgroup_enable_threaded() into cgroup_{save|restore}_control() so
that mulitple cgroups can be handled.
* Updating all threaded descendants' ->dom_cgrp to point to the new
dom_cgrp when enabling threaded mode.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Reported-by: Amin Jamali <ajamali@pivotal.io>
Reported-by: Joao De Almeida Pereira <jpereira@pivotal.io>
Link: https://lore.kernel.org/r/CAKgNAkhHYCMn74TCNiMJ=ccLd7DcmXSbvw3CbZ1YREeG7iJM5g@mail.gmail.com
Fixes: 454000adaa ("cgroup: introduce cgroup->dom_cgrp and threaded css_set handling")
Cc: stable@vger.kernel.org # v4.14+
The comment related to nr_iowait_cpu() and get_iowait_load() confuses
cpufreq with cpuidle and is not very useful for this reason, so fix it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux PM <linux-pm@vger.kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: e33a9bba85 "sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler"
Link: http://lkml.kernel.org/r/3803514.xkx7zY50tF@aspire.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Minor conflict in net/core/rtnetlink.c, David Ahern's bug fix in 'net'
overlapped the renaming of a netlink attribute in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
We reserve 128 bytes for struct siginfo but only use about 48 bytes on
64bit and 32 bytes on 32bit. Someday we might use more but it is unlikely
to be anytime soon.
Userspace seems content with just enough bytes of siginfo to implement
sigqueue. Or in the case of checkpoint/restart reinjecting signals
the kernel has sent.
Reducing the stack footprint and the work to copy siginfo around from
2 cachelines to 1 cachelines seems worth doing even if I don't have
benchmarks to show a performance difference.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Linus recently observed that if we did not worry about the padding
member in struct siginfo it is only about 48 bytes, and 48 bytes is
much nicer than 128 bytes for allocating on the stack and copying
around in the kernel.
The obvious thing of only adding the padding when userspace is
including siginfo.h won't work as there are sigframe definitions in
the kernel that embed struct siginfo.
So split siginfo in two; kernel_siginfo and siginfo. Keeping the
traditional name for the userspace definition. While the version that
is used internally to the kernel and ultimately will not be padded to
128 bytes is called kernel_siginfo.
The definition of struct kernel_siginfo I have put in include/signal_types.h
A set of buildtime checks has been added to verify the two structures have
the same field offsets.
To make it easy to verify the change kernel_siginfo retains the same
size as siginfo. The reduction in size comes in a following change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
In preparation for using a smaller version of siginfo in the kernel
introduce copy_siginfo_from_user and use it when siginfo is copied from
userspace.
Make the pattern for using copy_siginfo_from_user and
copy_siginfo_from_user32 to capture the return value and return that
value on error.
This is a necessary prerequisite for using a smaller siginfo
in the kernel than the kernel exports to userspace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Rework the defintion of struct siginfo so that the array padding
struct siginfo to SI_MAX_SIZE can be placed in a union along side of
the rest of the struct siginfo members. The result is that we no
longer need the __ARCH_SI_PREAMBLE_SIZE or SI_PAD_SIZE definitions.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The kernel needs to validate that the contents of struct siginfo make
sense as siginfo is copied into the kernel, so that the proper union
members can be put in the appropriate locations. The field si_signo
is a fundamental part of that validation. As such changing the
contents of si_signo after the validation make no sense and can result
in nonsense values in the kernel.
As such simply fail if someone is silly enough to set si_signo out of
sync with the signal number passed to sigqueueinfo.
I don't expect a problem as glibc's sigqueue implementation sets
"si_signo = sig" and CRIU just returns to the kernel what the kernel
gave to it.
If there is some application that calls sigqueueinfo directly that has
a problem with this added sanity check we can revisit this when we see
what kind of crazy that application is doing.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
When moving all of the architectures specific si_codes into
siginfo.h, I apparently overlooked EMT_TAGOVF. Move it now.
Remove the now redundant test in siginfo_layout for SIGEMT
as now NSIGEMT is always defined.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
If CONFIG_WW_MUTEX_SELFTEST=y is enabled, booting an image
in an arm64 virtual machine results in the following
traceback if 8 CPUs are enabled:
DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current)
WARNING: CPU: 2 PID: 537 at kernel/locking/mutex.c:1033 __mutex_unlock_slowpath+0x1a8/0x2e0
...
Call trace:
__mutex_unlock_slowpath()
ww_mutex_unlock()
test_cycle_work()
process_one_work()
worker_thread()
kthread()
ret_from_fork()
If requesting b_mutex fails with -EDEADLK, the error variable
is reassigned to the return value from calling ww_mutex_lock
on a_mutex again. If this call fails, a_mutex is not locked.
It is, however, unconditionally unlocked subsequently, causing
the reported warning. Fix the problem by using two error variables.
With this change, the selftest still fails as follows:
cyclic deadlock not resolved, ret[7/8] = -35
However, the traceback is gone.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: d1b42b800e ("locking/ww_mutex: Add kselftests for resolving ww_mutex cyclic deadlocks")
Link: http://lkml.kernel.org/r/1538516929-9734-1-git-send-email-linux@roeck-us.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When __lock_release() is called, the most likely unlock scenario is
on the innermost lock in the chain. In this case, we can skip some of
the checks and provide a faster path to completion.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1538511560-10090-4-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The static __lock_acquire() function has only two callers:
1) lock_acquire()
2) reacquire_held_locks()
In lock_acquire(), raw_local_irq_save() is called beforehand. So
IRQs must have been disabled. So the check:
DEBUG_LOCKS_WARN_ON(!irqs_disabled())
is kind of redundant in this case. So move the above check
to reacquire_held_locks() to eliminate redundant code in the
lock_acquire() path.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1538511560-10090-3-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The inline function add_chain_cache_classes() is defined, but has no
caller. Just remove it.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1538511560-10090-2-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds new BPF helper functions, bpf_sk_lookup_tcp() and
bpf_sk_lookup_udp() which allows BPF programs to find out if there is a
socket listening on this host, and returns a socket pointer which the
BPF program can then access to determine, for instance, whether to
forward or drop traffic. bpf_sk_lookup_xxx() may take a reference on the
socket, so when a BPF program makes use of this function, it must
subsequently pass the returned pointer into the newly added sk_release()
to return the reference.
By way of example, the following pseudocode would filter inbound
connections at XDP if there is no corresponding service listening for
the traffic:
struct bpf_sock_tuple tuple;
struct bpf_sock_ops *sk;
populate_tuple(ctx, &tuple); // Extract the 5tuple from the packet
sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof tuple, netns, 0);
if (!sk) {
// Couldn't find a socket listening for this traffic. Drop.
return TC_ACT_SHOT;
}
bpf_sk_release(sk, 0);
return TC_ACT_OK;
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Allow helper functions to acquire a reference and return it into a
register. Specific pointer types such as the PTR_TO_SOCKET will
implicitly represent such a reference. The verifier must ensure that
these references are released exactly once in each path through the
program.
To achieve this, this commit assigns an id to the pointer and tracks it
in the 'bpf_func_state', then when the function or program exits,
verifies that all of the acquired references have been freed. When the
pointer is passed to a function that frees the reference, it is removed
from the 'bpf_func_state` and all existing copies of the pointer in
registers are marked invalid.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
An upcoming commit will need very similar copy/realloc boilerplate, so
refactor the existing stack copy/realloc functions into macros to
simplify it.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Teach the verifier a little bit about a new type of pointer, a
PTR_TO_SOCKET. This pointer type is accessed from BPF through the
'struct bpf_sock' structure.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This check will be reused by an upcoming commit for conditional jump
checks for sockets. Refactor it a bit to simplify the later commit.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The array "reg_type_str" provides canonical formatting of register
types, however a couple of places would previously check whether a
register represented the context and write the name "context" directly.
An upcoming commit will add another pointer type to these statements, so
to provide more accurate error messages in the verifier, update these
error messages to use "reg_type_str" instead.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
An upcoming commit will add another two pointer types that need very
similar behaviour, so generalise this function now.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Add this iterator for spilled registers, it concentrates the details of
how to get the current frame's spilled registers into a single macro
while clarifying the intention of the code which is calling the macro.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
CON_PRINTBUFFER console registration requires us to do several
preparation steps:
- Rollback console_seq to replay logbuf messages which were already
seen on other consoles;
- Set exclusive_console flag so console_unlock() will ->write() logbuf
messages only to the exclusive_console driver.
The way we do it, however, is a bit racy
logbuf_lock_irqsave(flags);
console_seq = syslog_seq;
console_idx = syslog_idx;
logbuf_unlock_irqrestore(flags);
<< preemption enabled
<< irqs enabled
exclusive_console = newcon;
console_unlock();
We rollback console_seq under logbuf_lock with IRQs disabled, but
we set exclusive_console with local IRQs enabled and logbuf unlocked.
If the system oops-es or panic-s before we set exclusive_console - and
given that we have IRQs and preemption enabled there is such a
possibility - we will re-play all logbuf messages to every registered
console, which may be a bit annoying and time consuming.
Move exclusive_console assignment to the same IRQs-disabled and
logbuf_lock-protected section where we rollback console_seq.
Link: http://lkml.kernel.org/r/20180928095304.9972-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The variable "exclusive_console" is used to reply all existing messages
on a newly registered console. It is cleared when all messages are out.
The problem is that new messages might appear in the meantime. These
are then visible only on the exclusive console.
The obvious solution is to clear "exclusive_console" after we replay
all messages that were already proceed before we started the reply.
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Link: http://lkml.kernel.org/r/20180913123406.14378-1-pmladek@suse.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Explicitly forbid creating cgroup local storage maps with zero value
size, as it makes no sense and might even cause a panic.
Reported-by: syzbot+18628320d3b14a5c459c@syzkaller.appspotmail.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Automatic NUMA Balancing uses a multi-stage pass to decide whether a page
should migrate to a local node. This filter avoids excessive ping-ponging
if a page is shared or used by threads that migrate cross-node frequently.
Threads inherit both page tables and the preferred node ID from the
parent. This means that threads can trigger hinting faults earlier than
a new task which delays scanning for a number of seconds. As it can be
load balanced very early in its lifetime there can be an unnecessary delay
before it starts migrating thread-local data. This patch migrates private
pages faster early in the lifetime of a thread using the sequence counter
as an identifier of new tasks.
With this patch applied, STREAM performance is the same as 4.17 even though
processes are not spread cross-node prematurely. Other workloads showed
a mix of minor gains and losses. This is somewhat expected most workloads
are not very sensitive to the starting conditions of a process.
4.19.0-rc5 4.19.0-rc5 4.17.0
numab-v1r1 fastmigrate-v1r1 vanilla
MB/sec copy 43298.52 ( 0.00%) 47335.46 ( 9.32%) 47219.24 ( 9.06%)
MB/sec scale 30115.06 ( 0.00%) 32568.12 ( 8.15%) 32527.56 ( 8.01%)
MB/sec add 32825.12 ( 0.00%) 36078.94 ( 9.91%) 35928.02 ( 9.45%)
MB/sec triad 32549.52 ( 0.00%) 35935.94 ( 10.40%) 35969.88 ( 10.51%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001100525.29789-3-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull v4.20 RCU changes from Paul E. McKenney:
- Documentation updates, including some good-eye catches from
Joel Fernandes.
- SRCU updates, most notably changes enabling call_srcu() to be
invoked very early in the boot sequence.
- Torture-test updates, including some preliminary work towards
making rcutorture better able to find problems that result in
insufficient grace-period forward progress.
- Consolidate the RCU-bh, RCU-preempt, and RCU-sched flavors into
a single flavor similar to RCU-sched in !PREEMPT kernels and
into a single flavor similar to RCU-preempt (but also waiting
on preempt-disabled sequences of code) in PREEMPT kernels. This
branch also includes a refactoring of rcu_{nmi,irq}_{enter,exit}()
from Byungchul Park.
- Now that there is only one RCU flavor in any given running kernel,
the many "rsp" pointers are no longer required, and this cleanup
series removes them.
- This branch carries out additional cleanups made possible by
the RCU flavor consolidation, including inlining how-trivial
functions, updating comments and definitions, and removing
now-unneeded rcutorture scenarios.
- Initial changes to RCU to better promote forward progress of
grace periods, including fixing a bug found by Marius Hillenbrand
and David Woodhouse, with the fix suggested by Peter Zijlstra.
- Now that there is only one flavor of RCU in any running kernel,
there is also only on rcu_data structure per CPU. This means
that the rcu_dynticks structure can be merged into the rcu_data
structure, a task taken on by this branch. This branch also
contains a -rt-related fix from Mike Galbraith.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A CFS (SCHED_OTHER, SCHED_BATCH or SCHED_IDLE policy) task's
se->runnable_weight must always be in sync with its se->load.weight.
se->runnable_weight is set to se->load.weight when the task is
forked (init_entity_runnable_average()) or reniced (reweight_entity()).
There are two cases in set_load_weight() which since they currently only
set se->load.weight could lead to a situation in which se->load.weight
is different to se->runnable_weight for a CFS task:
(1) A task switches to SCHED_IDLE.
(2) A SCHED_FIFO, SCHED_RR or SCHED_DEADLINE task which has been reniced
(during which only its static priority gets set) switches to
SCHED_OTHER or SCHED_BATCH.
Set se->runnable_weight to se->load.weight in these two cases to prevent
this. This eliminates the need to explicitly set it to se->load.weight
during PELT updates in the CFS scheduler fastpath.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/20180803140538.1178-1-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
LB_BIAS allows the adjustment on how conservative load should be
balanced.
The rq->cpu_load[idx] array is used for this functionality. It contains
weighted CPU load decayed average values over different intervals
(idx = 1..4). Idx = 0 is the weighted CPU load itself.
The values are updated during scheduler_tick, before idle balance and at
nohz exit.
There are 5 different types of idx's per sched domain (sd). Each of them
is used to index into the rq->cpu_load[idx] array in a specific scenario
(busy, idle and newidle for load balancing, forkexec for wake-up
slow-path load balancing and wake for affine wakeup based on weight).
Only the sd idx's for busy and idle load balancing are set to 2,3 or 1,2
respectively. All the other sd idx's are set to 0.
Conservative load balancing is achieved for sd idx's >= 1 by using the
min/max (source_load()/target_load()) value between the current weighted
CPU load and the rq->cpu_load[sd idx -1] for the busiest(idlest)/local
CPU load in load balancing or vice versa in the wake-up slow-path load
balancing.
There is no conservative balancing for sd idx = 0 since only current
weighted CPU load is used in this case.
It is very likely that LB_BIAS' influence on load balancing can be
neglected (see test results below). This is further supported by:
(1) Weighted CPU load today is by itself a decayed average value (PELT)
(cfs_rq->avg->runnable_load_avg) and not the instantaneous load
(rq->load.weight) it was when LB_BIAS was introduced.
(2) Sd imbalance_pct is used for CPU_NEWLY_IDLE and CPU_NOT_IDLE (relate
to sd's newidle and busy idx) in find_busiest_group() when comparing
busiest and local avg load to make load balancing even more
conservative.
(3) The sd forkexec and newidle idx are always set to 0 so there is no
adjustment on how conservatively load balancing is done here.
(4) Affine wakeup based on weight (wake_affine_weight()) will not be
impacted since the sd wake idx is always set to 0.
Let's disable LB_BIAS by default for a few kernel releases to make sure
that no workload and no scheduler topology is affected. The benefit of
being able to remove the LB_BIAS dependency from source_load() and
target_load() is that the entire rq->cpu_load[idx] code could be removed
in this case.
It is really hard to say if there is no regression w/o testing this with
a lot of different workloads on a lot of different platforms, especially
NUMA machines.
The following 104 LKP (Linux Kernel Performance) tests were run by the
0-Day guys mostly on multi-socket hosts with a larger number of logical
cpus (88, 192).
The base for the test was commit b3dae109fa ("sched/swait: Rename to
exclusive") (tip/sched/core v4.18-rc1).
Only 2 out of the 104 tests had a significant change in one of the
metrics (fsmark/1x-1t-1HDD-btrfs-nfsv4-4M-60G-NoSync-performance +7%
files_per_sec, unixbench/300s-100%-syscall-performance -11% score).
Tests which showed a change in one of the metrics are marked with a '*'
and this change is listed as well.
(a) lkp-bdw-ep3:
88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz 64G
dd-write/10m-1HDD-cfq-btrfs-100dd-performance
fsmark/1x-1t-1HDD-xfs-nfsv4-4M-60G-NoSync-performance
* fsmark/1x-1t-1HDD-btrfs-nfsv4-4M-60G-NoSync-performance
7.50 7% 8.00 ± 6% fsmark.files_per_sec
fsmark/1x-1t-1HDD-btrfs-nfsv4-4M-60G-fsyncBeforeClose-performance
fsmark/1x-1t-1HDD-btrfs-4M-60G-NoSync-performance
fsmark/1x-1t-1HDD-btrfs-4M-60G-fsyncBeforeClose-performance
kbuild/300s-50%-vmlinux_prereq-performance
kbuild/300s-200%-vmlinux_prereq-performance
kbuild/300s-50%-vmlinux_prereq-performance-1HDD-ext4
kbuild/300s-200%-vmlinux_prereq-performance-1HDD-ext4
(b) lkp-skl-4sp1:
192 threads Intel(R) Xeon(R) Platinum 8160 768G
dbench/100%-performance
ebizzy/200%-100x-10s-performance
hackbench/1600%-process-pipe-performance
iperf/300s-cs-localhost-tcp-performance
iperf/300s-cs-localhost-udp-performance
perf-bench-numa-mem/2t-300M-performance
perf-bench-sched-pipe/10000000ops-process-performance
perf-bench-sched-pipe/10000000ops-threads-performance
schbench/2-16-300-30000-30000-performance
tbench/100%-cs-localhost-performance
(c) lkp-bdw-ep6:
88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz 128G
stress-ng/100%-60s-pipe-performance
unixbench/300s-1-whetstone-double-performance
unixbench/300s-1-shell1-performance
unixbench/300s-1-shell8-performance
unixbench/300s-1-pipe-performance
* unixbench/300s-1-context1-performance
312 315 unixbench.score
unixbench/300s-1-spawn-performance
unixbench/300s-1-syscall-performance
unixbench/300s-1-dhry2reg-performance
unixbench/300s-1-fstime-performance
unixbench/300s-1-fsbuffer-performance
unixbench/300s-1-fsdisk-performance
unixbench/300s-100%-whetstone-double-performance
unixbench/300s-100%-shell1-performance
unixbench/300s-100%-shell8-performance
unixbench/300s-100%-pipe-performance
unixbench/300s-100%-context1-performance
unixbench/300s-100%-spawn-performance
* unixbench/300s-100%-syscall-performance
3571 ± 3% -11% 3183 ± 4% unixbench.score
unixbench/300s-100%-dhry2reg-performance
unixbench/300s-100%-fstime-performance
unixbench/300s-100%-fsbuffer-performance
unixbench/300s-100%-fsdisk-performance
unixbench/300s-1-execl-performance
unixbench/300s-100%-execl-performance
* will-it-scale/brk1-performance
365004 360387 will-it-scale.per_thread_ops
* will-it-scale/dup1-performance
432401 437596 will-it-scale.per_thread_ops
will-it-scale/eventfd1-performance
will-it-scale/futex1-performance
will-it-scale/futex2-performance
will-it-scale/futex3-performance
will-it-scale/futex4-performance
will-it-scale/getppid1-performance
will-it-scale/lock1-performance
will-it-scale/lseek1-performance
will-it-scale/lseek2-performance
* will-it-scale/malloc1-performance
47025 45817 will-it-scale.per_thread_ops
77499 76529 will-it-scale.per_process_ops
will-it-scale/malloc2-performance
* will-it-scale/mmap1-performance
123399 120815 will-it-scale.per_thread_ops
152219 149833 will-it-scale.per_process_ops
* will-it-scale/mmap2-performance
107327 104714 will-it-scale.per_thread_ops
136405 133765 will-it-scale.per_process_ops
will-it-scale/open1-performance
* will-it-scale/open2-performance
171570 168805 will-it-scale.per_thread_ops
532644 526202 will-it-scale.per_process_ops
will-it-scale/page_fault1-performance
will-it-scale/page_fault2-performance
will-it-scale/page_fault3-performance
will-it-scale/pipe1-performance
will-it-scale/poll1-performance
* will-it-scale/poll2-performance
176134 172848 will-it-scale.per_thread_ops
281361 275053 will-it-scale.per_process_ops
will-it-scale/posix_semaphore1-performance
will-it-scale/pread1-performance
will-it-scale/pread2-performance
will-it-scale/pread3-performance
will-it-scale/pthread_mutex1-performance
will-it-scale/pthread_mutex2-performance
will-it-scale/pwrite1-performance
will-it-scale/pwrite2-performance
will-it-scale/pwrite3-performance
* will-it-scale/read1-performance
1190563 1174833 will-it-scale.per_thread_ops
* will-it-scale/read2-performance
1105369 1080427 will-it-scale.per_thread_ops
will-it-scale/readseek1-performance
* will-it-scale/readseek2-performance
261818 259040 will-it-scale.per_thread_ops
will-it-scale/readseek3-performance
* will-it-scale/sched_yield-performance
2408059 2382034 will-it-scale.per_thread_ops
will-it-scale/signal1-performance
will-it-scale/unix1-performance
will-it-scale/unlink1-performance
will-it-scale/unlink2-performance
* will-it-scale/write1-performance
976701 961588 will-it-scale.per_thread_ops
* will-it-scale/writeseek1-performance
831898 822448 will-it-scale.per_thread_ops
* will-it-scale/writeseek2-performance
228248 225065 will-it-scale.per_thread_ops
* will-it-scale/writeseek3-performance
226670 224058 will-it-scale.per_thread_ops
will-it-scale/context_switch1-performance
aim7/performance-fork_test-2000
* aim7/performance-brk_test-3000
74869 76676 aim7.jobs-per-min
aim7/performance-disk_cp-3000
aim7/performance-disk_rd-3000
aim7/performance-sieve-3000
aim7/performance-page_test-3000
aim7/performance-creat-clo-3000
aim7/performance-mem_rtns_1-8000
aim7/performance-disk_wrt-8000
aim7/performance-pipe_cpy-8000
aim7/performance-ram_copy-8000
(d) lkp-avoton3:
8 threads Intel(R) Atom(TM) CPU C2750 @ 2.40GHz 16G
netperf/ipv4-900s-200%-cs-localhost-TCP_STREAM-performance
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Li Zhijian <zhijianx.li@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180809135753.21077-1-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Create a config for enabling irq load tracking in the scheduler.
irq load tracking is useful only when irq or paravirtual time is
accounted but it's only possible with SMP for now.
Also use __maybe_unused to remove the compilation warning in
update_rq_clock_task() that has been introduced by:
2e62c4743a ("sched/fair: Remove #ifdefs from scale_rt_capacity()")
Suggested-by: Ingo Molnar <mingo@redhat.com>
Reported-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Reported-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: dou_liyang@163.com
Fixes: 2e62c4743a ("sched/fair: Remove #ifdefs from scale_rt_capacity()")
Link: http://lkml.kernel.org/r/1537867062-27285-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some of the scheduling tracepoints allow the perf_tp_event
code to write to ring buffer under different cpu than the
code is running on.
This results in corrupted ring buffer data demonstrated in
following perf commands:
# perf record -e 'sched:sched_switch,sched:sched_wakeup' perf bench sched messaging
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run
Total time: 0.383 [sec]
[ perf record: Woken up 8 times to write data ]
0x42b890 [0]: failed to process type: -1765585640
[ perf record: Captured and wrote 4.825 MB perf.data (29669 samples) ]
# perf report --stdio
0x42b890 [0]: failed to process type: -1765585640
The reason for the corruption are some of the scheduling tracepoints,
that have __perf_task dfined and thus allow to store data to another
cpu ring buffer:
sched_waking
sched_wakeup
sched_wakeup_new
sched_stat_wait
sched_stat_sleep
sched_stat_iowait
sched_stat_blocked
The perf_tp_event function first store samples for current cpu
related events defined for tracepoint:
hlist_for_each_entry_rcu(event, head, hlist_entry)
perf_swevent_event(event, count, &data, regs);
And then iterates events of the 'task' and store the sample
for any task's event that passes tracepoint checks:
ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->attr.type != PERF_TYPE_TRACEPOINT)
continue;
if (event->attr.config != entry->type)
continue;
perf_swevent_event(event, count, &data, regs);
}
Above code can race with same code running on another cpu,
ending up with 2 cpus trying to store under the same ring
buffer, which is specifically not allowed.
This patch prevents the problem, by allowing only events with the same
current cpu to receive the event.
NOTE: this requires the use of (per-task-)per-cpu buffers for this
feature to work; perf-record does this.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
[peterz: small edits to Changelog]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: e6dab5ffab ("perf/trace: Add ability to set a target task for events")
Link: http://lkml.kernel.org/r/20180923161343.GB15054@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we unregister a PMU, we fail to serialize the @pmu_idr properly.
Fix that by doing the entire thing under pmu_lock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 2e80a82a49 ("perf: Dynamic pmu types")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 1948367768 ("jump_label: Annotate entries that operate on
__init code earlier") refactored the code that manages runtime
patching of jump labels in modules that are tied to static keys
defined in other modules or in the core kernel.
In the latter case, we may iterate over the static_key_mod linked
list until we hit the entry for the core kernel, whose 'mod' field
will be NULL, and attempt to dereference it to get at its 'state'
member.
So let's add a non-NULL check: this forces the 'init' argument of
__jump_label_update() to false for static keys that are defined in
the core kernel, which is appropriate given that __init annotated
jump_label entries in the core kernel should no longer be active
at this point (i.e., when loading modules).
Fixes: 1948367768 ("jump_label: Annotate entries that operate on ...")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20181001081324.11553-1-ard.biesheuvel@linaro.org
Previously, on typical consumer laptops, pressing a key on the keyboard
when the system is in suspend would cause it to wake up (default or
unconditional behaviour). This happens because the EC generates a SCI
interrupt in this scenario.
That is no longer true on modern laptops based on Intel WhiskeyLake,
including Acer Swift SF314-55G, Asus UX333FA, Asus UX433FN and Asus
UX533FD. We confirmed with Asus EC engineers that the "Modern Standby"
design has been modified so that the EC no longer generates a SCI
in this case; the keyboard controller itself should be used for wakeup.
In order to retain the standard behaviour of being able to use the
keyboard to wake up the system, enable serio wakeups by default on
platforms that are using s2idle.
Link: https://lkml.kernel.org/r/CAB4CAwfQ0mPMqCLp95TVjw4J0r5zKPWkSvvkK4cpZUGE--w8bQ@mail.gmail.com
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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Merge tag 'v4.19-rc6' into for-4.20/block
Merge -rc6 in, for two reasons:
1) Resolve a trivial conflict in the blk-mq-tag.c documentation
2) A few important regression fixes went into upstream directly, so
they aren't in the 4.20 branch.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* tag 'v4.19-rc6': (780 commits)
Linux 4.19-rc6
MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c
cpufreq: qcom-kryo: Fix section annotations
perf/core: Add sanity check to deal with pinned event failure
xen/blkfront: correct purging of persistent grants
Revert "xen/blkfront: When purging persistent grants, keep them in the buffer"
selftests/powerpc: Fix Makefiles for headers_install change
blk-mq: I/O and timer unplugs are inverted in blktrace
dax: Fix deadlock in dax_lock_mapping_entry()
x86/boot: Fix kexec booting failure in the SEV bit detection code
bcache: add separate workqueue for journal_write to avoid deadlock
drm/amd/display: Fix Edid emulation for linux
drm/amd/display: Fix Vega10 lightup on S3 resume
drm/amdgpu: Fix vce work queue was not cancelled when suspend
Revert "drm/panel: Add device_link from panel device to DRM device"
xen/blkfront: When purging persistent grants, keep them in the buffer
clocksource/drivers/timer-atmel-pit: Properly handle error cases
block: fix deadline elevator drain for zoned block devices
ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge
drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set
...
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This way an architecture with less than 4G of RAM can support dma_mask
smaller than 32-bit without a ZONE_DMA. Apparently that is a common
case on powerpc.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Instead of rejecting devices with a too small bus_dma_mask we can handle
by taking the bus dma_mask into account for allocations and bounce
buffering decisions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
We need to take the DMA offset and encryption bit into account when
selecting a zone. User the opportunity to factor out the zone
selection into a helper for reuse.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
This is somewhat modelled after the powerpc version, and differs from
the legacy fallback in use fls64 instead of pointlessly splitting up the
address into low and high dwords and in that it takes (__)phys_to_dma
into account.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Explicitly forbid creating map of per-cpu cgroup local storages.
This behavior matches the behavior of shared cgroup storages.
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit introduced per-cpu cgroup local storage.
Per-cpu cgroup local storage is very similar to simple cgroup storage
(let's call it shared), except all the data is per-cpu.
The main goal of per-cpu variant is to implement super fast
counters (e.g. packet counters), which don't require neither
lookups, neither atomic operations.
>From userspace's point of view, accessing a per-cpu cgroup storage
is similar to other per-cpu map types (e.g. per-cpu hashmaps and
arrays).
Writing to a per-cpu cgroup storage is not atomic, but is performed
by copying longs, so some minimal atomicity is here, exactly
as with other per-cpu maps.
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
To simplify the following introduction of per-cpu cgroup storage,
let's rework a bit a mechanism of passing a pointer to a cgroup
storage into the bpf_get_local_storage(). Let's save a pointer
to the corresponding bpf_cgroup_storage structure, instead of
a pointer to the actual buffer.
It will help us to handle per-cpu storage later, which has
a different way of accessing to the actual data.
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
In order to introduce per-cpu cgroup storage, let's generalize
bpf cgroup core to support multiple cgroup storage types.
Potentially, per-node cgroup storage can be added later.
This commit is mostly a formal change that replaces
cgroup_storage pointer with a array of cgroup_storage pointers.
It doesn't actually introduce a new storage type,
it will be done later.
Each bpf program is now able to have one cgroup storage of each type.
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The sigaltstack(2) system call fails with -ENOMEM if the new alternative
signal stack is found to be smaller than SIGMINSTKSZ. On architectures
such as arm64, where the native value for SIGMINSTKSZ is larger than
the compat value, this can result in an unexpected error being reported
to a compat task. See, for example:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=904385
This patch fixes the problem by extending do_sigaltstack to take the
minimum signal stack size as an additional parameter, allowing the
native and compat system call entry code to pass in their respective
values. COMPAT_SIGMINSTKSZ is just defined as SIGMINSTKSZ if it has not
been defined by the architecture.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Reported-by: Steve McIntyre <steve.mcintyre@arm.com>
Tested-by: Steve McIntyre <93sam@debian.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On a DT based system, we use the of_node full name to name the
corresponding irq domain. We expect that name to be unique, so so that
domains with the same base name won't clash (this happens on multi-node
topologies, for example).
Since a7e4cfb0a7 ("of/fdt: only store the device node basename in
full_name"), of_node_full_name() lies and only returns the basename. This
breaks the above requirement, and we end-up with only a subset of the
domains in /sys/kernel/debug/irq/domains.
Let's reinstate the feature by using the fancy new %pOF format specifier,
which happens to do the right thing.
Fixes: a7e4cfb0a7 ("of/fdt: only store the device node basename in full_name")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20181001100522.180054-3-marc.zyngier@arm.com
When removing a debugfs file for a given irq domain, we fail to clear the
corresponding field, meaning that the corresponding domain won't be created
again if we need to do so.
It turns out that this is exactly what irq_domain_update_bus_token does
(delete old file, update domain name, recreate file).
This doesn't have any impact other than making debug more difficult, but we
do value ease of debugging... So clear the debugfs_file field.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20181001100522.180054-2-marc.zyngier@arm.com
Thomas writes:
"A single fix for a missing sanity check when a pinned event is tried
to be read on the wrong CPU due to a legit event scheduling failure."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Add sanity check to deal with pinned event failure
cgroup_storage_update_elem() shouldn't accept any flags
argument values except BPF_ANY and BPF_EXIST to guarantee
the backward compatibility, had a new flag value been added.
Fixes: de9cbbaadb ("bpf: introduce cgroup storage maps")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Currently, helper bpf_get_current_cgroup_id() is not permitted
for CGROUP_DEVICE type of programs. If the helper is used
in such cases, the verifier will log the following error:
0: (bf) r6 = r1
1: (69) r7 = *(u16 *)(r6 +0)
2: (85) call bpf_get_current_cgroup_id#80
unknown func bpf_get_current_cgroup_id#80
The bpf_get_current_cgroup_id() is useful for CGROUP_DEVICE
type of programs in order to customize action based on cgroup id.
This patch added such a support.
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The __jump_table sections emitted into the core kernel and into
each module consist of statically initialized references into
other parts of the code, and with the exception of entries that
point into init code, which are defused at post-init time, these
data structures are never modified.
So let's move them into the ro_after_init section, to prevent them
from being corrupted inadvertently by buggy code, or deliberately
by an attacker.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: https://lkml.kernel.org/r/20180919065144.25010-9-ard.biesheuvel@linaro.org
Jump table entries are mostly read-only, with the exception of the
init and module loader code that defuses entries that point into init
code when the code being referred to is freed.
For robustness, it would be better to move these entries into the
ro_after_init section, but clearing the 'code' member of each jump
table entry referring to init code at module load time races with the
module_enable_ro() call that remaps the ro_after_init section read
only, so we'd like to do it earlier.
So given that whether such an entry refers to init code can be decided
much earlier, we can pull this check forward. Since we may still need
the code entry at this point, let's switch to setting a low bit in the
'key' member just like we do to annotate the default state of a jump
table entry.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-8-ard.biesheuvel@linaro.org
To reduce the size taken up by absolute references in jump label
entries themselves and the associated relocation records in the
.init segment, add support for emitting them as relative references
instead.
Note that this requires some extra care in the sorting routine, given
that the offsets change when entries are moved around in the jump_entry
table.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-3-ard.biesheuvel@linaro.org
In preparation of allowing architectures to use relative references
in jump_label entries [which can dramatically reduce the memory
footprint], introduce abstractions for references to the 'code' and
'key' members of struct jump_entry.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-2-ard.biesheuvel@linaro.org
STIBP is a feature provided by certain Intel ucodes / CPUs. This feature
(once enabled) prevents cross-hyperthread control of decisions made by
indirect branch predictors.
Enable this feature if
- the CPU is vulnerable to spectre v2
- the CPU supports SMT and has SMT siblings online
- spectre_v2 mitigation autoselection is enabled (default)
After some previous discussion, this leaves STIBP on all the time, as wrmsr
on crossing kernel boundary is a no-no. This could perhaps later be a bit
more optimized (like disabling it in NOHZ, experiment with disabling it in
idle, etc) if needed.
Note that the synchronization of the mask manipulation via newly added
spec_ctrl_mutex is currently not strictly needed, as the only updater is
already being serialized by cpu_add_remove_lock, but let's make this a
little bit more future-proof.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "WoodhouseDavid" <dwmw@amazon.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: "SchauflerCasey" <casey.schaufler@intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/nycvar.YFH.7.76.1809251438240.15880@cbobk.fhfr.pm
Currently, IBPB is only issued in cases when switching into a non-dumpable
process, the rationale being to protect such 'important and security
sensitive' processess (such as GPG) from data leaking into a different
userspace process via spectre v2.
This is however completely insufficient to provide proper userspace-to-userpace
spectrev2 protection, as any process can poison branch buffers before being
scheduled out, and the newly scheduled process immediately becomes spectrev2
victim.
In order to minimize the performance impact (for usecases that do require
spectrev2 protection), issue the barrier only in cases when switching between
processess where the victim can't be ptraced by the potential attacker (as in
such cases, the attacker doesn't have to bother with branch buffers at all).
[ tglx: Split up PTRACE_MODE_NOACCESS_CHK into PTRACE_MODE_SCHED and
PTRACE_MODE_IBPB to be able to do ptrace() context tracking reasonably
fine-grained ]
Fixes: 18bf3c3ea8 ("x86/speculation: Use Indirect Branch Prediction Barrier in context switch")
Originally-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "WoodhouseDavid" <dwmw@amazon.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "SchauflerCasey" <casey.schaufler@intel.com>
Link: https://lkml.kernel.org/r/nycvar.YFH.7.76.1809251437340.15880@cbobk.fhfr.pm
This is the only location on kernel that has wrong spelling
of the container_of() helper. Fix it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Daniel Borkmann says:
====================
pull-request: bpf-next 2018-09-25
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Allow for RX stack hardening by implementing the kernel's flow
dissector in BPF. Idea was originally presented at netconf 2017 [0].
Quote from merge commit:
[...] Because of the rigorous checks of the BPF verifier, this
provides significant security guarantees. In particular, the BPF
flow dissector cannot get inside of an infinite loop, as with
CVE-2013-4348, because BPF programs are guaranteed to terminate.
It cannot read outside of packet bounds, because all memory accesses
are checked. Also, with BPF the administrator can decide which
protocols to support, reducing potential attack surface. Rarely
encountered protocols can be excluded from dissection and the
program can be updated without kernel recompile or reboot if a
bug is discovered. [...]
Also, a sample flow dissector has been implemented in BPF as part
of this work, from Petar and Willem.
[0] http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdf
2) Add support for bpftool to list currently active attachment
points of BPF networking programs providing a quick overview
similar to bpftool's perf subcommand, from Yonghong.
3) Fix a verifier pruning instability bug where a union member
from the register state was not cleared properly leading to
branches not being pruned despite them being valid candidates,
from Alexei.
4) Various smaller fast-path optimizations in XDP's map redirect
code, from Jesper.
5) Enable to recognize BPF_MAP_TYPE_REUSEPORT_SOCKARRAY maps
in bpftool, from Roman.
6) Remove a duplicate check in libbpf that probes for function
storage, from Taeung.
7) Fix an issue in test_progs by avoid checking for errno since
on success its value should not be checked, from Mauricio.
8) Fix unused variable warning in bpf_getsockopt() helper when
CONFIG_INET is not configured, from Anders.
9) Fix a compilation failure in the BPF sample code's use of
bpf_flow_keys, from Prashant.
10) Minor cleanups in BPF code, from Yue and Zhong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The patch adding the infrastructure failed to actually add the symbol
declaration, oops..
Fixes: faef87723a ("dma-noncoherent: add a arch_sync_dma_for_cpu_all hook")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Version bump conflict in batman-adv, take what's in net-next.
iavf conflict, adjustment of netdev_ops in net-next conflicting
with poll controller method removal in net.
Signed-off-by: David S. Miller <davem@davemloft.net>
Dave writes:
"Networking fixes:
1) Fix multiqueue handling of coalesce timer in stmmac, from Jose
Abreu.
2) Fix memory corruption in NFC, from Suren Baghdasaryan.
3) Don't write reserved bits in ravb driver, from Kazuya Mizuguchi.
4) SMC bug fixes from Karsten Graul, YueHaibing, and Ursula Braun.
5) Fix TX done race in mvpp2, from Antoine Tenart.
6) ipv6 metrics leak, from Wei Wang.
7) Adjust firmware version requirements in mlxsw, from Petr Machata.
8) Fix autonegotiation on resume in r8169, from Heiner Kallweit.
9) Fixed missing entries when dumping /proc/net/if_inet6, from Jeff
Barnhill.
10) Fix double free in devlink, from Dan Carpenter.
11) Fix ethtool regression from UFO feature removal, from Maciej
Żenczykowski.
12) Fix drivers that have a ndo_poll_controller() that captures the
cpu entirely on loaded hosts by trying to drain all rx and tx
queues, from Eric Dumazet.
13) Fix memory corruption with jumbo frames in aquantia driver, from
Friedemann Gerold."
* gitolite.kernel.org:/pub/scm/linux/kernel/git/davem/net: (79 commits)
net: mvneta: fix the remaining Rx descriptor unmapping issues
ip_tunnel: be careful when accessing the inner header
mpls: allow routes on ip6gre devices
net: aquantia: memory corruption on jumbo frames
tun: remove ndo_poll_controller
nfp: remove ndo_poll_controller
bnxt: remove ndo_poll_controller
bnx2x: remove ndo_poll_controller
mlx5: remove ndo_poll_controller
mlx4: remove ndo_poll_controller
i40evf: remove ndo_poll_controller
ice: remove ndo_poll_controller
igb: remove ndo_poll_controller
ixgb: remove ndo_poll_controller
fm10k: remove ndo_poll_controller
ixgbevf: remove ndo_poll_controller
ixgbe: remove ndo_poll_controller
bonding: use netpoll_poll_dev() helper
netpoll: make ndo_poll_controller() optional
rds: Fix build regression.
...
We assume to have only one reference counter for one uprobe.
Don't allow user to add multiple trace_uprobe entries having
same inode+offset but different reference counter.
Ex,
# echo "p:sdt_tick/loop2 /home/ravi/tick:0x6e4(0x10036)" > uprobe_events
# echo "p:sdt_tick/loop2_1 /home/ravi/tick:0x6e4(0xfffff)" >> uprobe_events
bash: echo: write error: Invalid argument
# dmesg
trace_kprobe: Reference counter offset mismatch.
There is one exception though:
When user is trying to replace the old entry with the new
one, we allow this if the new entry does not conflict with
any other existing entries.
Link: http://lkml.kernel.org/r/20180820044250.11659-4-ravi.bangoria@linux.ibm.com
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
We assume to have only one reference counter for one uprobe.
Don't allow user to register multiple uprobes having same
inode+offset but different reference counter.
Link: http://lkml.kernel.org/r/20180820044250.11659-3-ravi.bangoria@linux.ibm.com
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Userspace Statically Defined Tracepoints[1] are dtrace style markers
inside userspace applications. Applications like PostgreSQL, MySQL,
Pthread, Perl, Python, Java, Ruby, Node.js, libvirt, QEMU, glib etc
have these markers embedded in them. These markers are added by developer
at important places in the code. Each marker source expands to a single
nop instruction in the compiled code but there may be additional
overhead for computing the marker arguments which expands to couple of
instructions. In case the overhead is more, execution of it can be
omitted by runtime if() condition when no one is tracing on the marker:
if (reference_counter > 0) {
Execute marker instructions;
}
Default value of reference counter is 0. Tracer has to increment the
reference counter before tracing on a marker and decrement it when
done with the tracing.
Implement the reference counter logic in core uprobe. User will be
able to use it from trace_uprobe as well as from kernel module. New
trace_uprobe definition with reference counter will now be:
<path>:<offset>[(ref_ctr_offset)]
where ref_ctr_offset is an optional field. For kernel module, new
variant of uprobe_register() has been introduced:
uprobe_register_refctr(inode, offset, ref_ctr_offset, consumer)
No new variant for uprobe_unregister() because it's assumed to have
only one reference counter for one uprobe.
[1] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
Note: 'reference counter' is called as 'semaphore' in original Dtrace
(or Systemtap, bcc and even in ELF) documentation and code. But the
term 'semaphore' is misleading in this context. This is just a counter
used to hold number of tracers tracing on a marker. This is not really
used for any synchronization. So we are calling it a 'reference counter'
in kernel / perf code.
Link: http://lkml.kernel.org/r/20180820044250.11659-2-ravi.bangoria@linux.ibm.com
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
[Only trace_uprobe.c]
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
By utilizing a temporary variable, we can avoid adding another call to
strchr(). Instead, save the first call to a temp variable, and then use that
variable as the reference to set the event variable.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The previous patch in this series removed carrying around a pointer to
the css in blkg. However, the blkg association logic still relied on
taking a reference on the css to ensure we wouldn't fail in getting a
reference for the blkg.
Here the implicit dependency on the css is removed. The association
continues to rely on the tryget logic walking up the blkg tree. This
streamlines the three ways that association can happen: normal, swap,
and writeback.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Prior patches ensured that all bios are now associated with some blkg.
This now makes bio->bi_css unnecessary as blkg maintains a reference to
the blkcg already.
This patch removes the field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is possible (via shutdown()) for TCP socks to go trough TCP_CLOSE
state via tcp_disconnect() without actually calling tcp_close which
would then call our bpf_tcp_close() callback. Because of this a user
could disconnect a socket then put it in a LISTEN state which would
break our assumptions about sockets always being ESTABLISHED state.
To resolve this rely on the unhash hook, which is called in the
disconnect case, to remove the sock from the sockmap.
Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: 1aa12bdf1b ("bpf: sockmap, add sock close() hook to remove socks")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
After this patch we only allow socks that are in ESTABLISHED state or
are being added via a sock_ops event that is transitioning into an
ESTABLISHED state. By allowing sock_ops events we allow users to
manage sockmaps directly from sock ops programs. The two supported
sock_ops ops are BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB and
BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB.
Similar to TLS ULP this ensures sk_user_data is correct.
Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: 1aa12bdf1b ("bpf: sockmap, add sock close() hook to remove socks")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
consume_skb has taken the null pointer into account. hence it is safe
to remove the redundant null pointer check before consume_skb.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Make the clone and fork syscalls return EAGAIN when the limit on the
number of pids /proc/sys/kernel/pid_max is exceeded.
Currently, when the pid_max limit is exceeded, the kernel will return
ENOSPC from the fork and clone syscalls. This is contrary to the
documented behaviour, which explicitly calls out the pid_max case as one
where EAGAIN should be returned. It also leads to really confusing error
messages in userspace programs which will complain about a lack of disk
space when they fail to create processes/threads for this reason.
This error is being returned because alloc_pid() uses the idr api to find
a new pid; when there are none available, idr_alloc_cyclic() returns
-ENOSPC, and this is being propagated back to userspace.
This behaviour has been broken before, and was explicitly fixed in
commit 35f71bc0a0 ("fork: report pid reservation failure properly"),
so I think -EAGAIN is definitely the right thing to return in this case.
The current behaviour change dates from commit 95846ecf9d ("pid:
replace pid bitmap implementation with IDR AIP") and was I believe
unintentional.
This patch has no impact on the case where allocating a pid fails because
the child reaper for the namespace is dead; that case will still return
-ENOMEM.
Link: http://lkml.kernel.org/r/20180903111016.46461-1-ktsanaktsidis@zendesk.com
Fixes: 95846ecf9d ("pid: replace pid bitmap implementation with IDR AIP")
Signed-off-by: KJ Tsanaktsidis <ktsanaktsidis@zendesk.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Gargi Sharma <gs051095@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We can use the arch_dma_coherent_to_pfn hook to provide a ->get_sgtable
implementation. Note that this isn't an endorsement of this interface
(which is a horrible bad idea), but it is required to move arm64 over
to the generic code without a loss of functionality.
Signed-off-by: Christoph Hellwig <hch@lst.de>
The only functional differences (modulo a few missing fixes in the arch
code) is that architectures without coherent caches need a hook to
convert a virtual or dma address into a pfn, given that we don't have
the kernel linear mapping available for the otherwise easy virt_to_page
call. As a side effect we can support mmap of the per-device coherent
area even on architectures not providing the callback, and we make
previous dangerous default methods dma_common_mmap actually save for
non-coherent architectures by rejecting it without the right helper.
In addition to that we need a hook so that some architectures can
override the protection bits when mmaping a dma coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
All the cache maintainance is already stubbed out when not enabled,
but merging the two allows us to nicely handle the case where
cache maintainance is required for some devices, but not others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
Various architectures support both coherent and non-coherent dma on a
per-device basis. Move the dma_noncoherent flag from the mips archdata
field to struct device proper to prepare the infrastructure for reuse on
other architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch adding the infrastructure failed to actually add the symbol
declaration, oops..
Fixes: faef87723a ("dma-noncoherent: add a arch_sync_dma_for_cpu_all hook")
Signed-off-by: Christoph Hellwig <hch@lst.de>
early_cma does not check input argument before passing it to
simple_strtoull. The argument would be a NULL pointer if "cma", without
its value, is set in command line and thus causes the following panic.
PANIC: early exception 0xe3 IP 10:ffffffffa3e9db8d error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc3-yocto-standard+ #7
[ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70
...
[ 0.000000] Call Trace:
[ 0.000000] simple_strtoull+0x29/0x70
[ 0.000000] memparse+0x26/0x90
[ 0.000000] early_cma+0x17/0x6a
[ 0.000000] do_early_param+0x57/0x8e
[ 0.000000] parse_args+0x208/0x320
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_options+0x29/0x2d
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_param+0x36/0x4d
[ 0.000000] setup_arch+0x336/0x99e
[ 0.000000] start_kernel+0x6f/0x4e6
[ 0.000000] x86_64_start_reservations+0x24/0x26
[ 0.000000] x86_64_start_kernel+0x6f/0x72
[ 0.000000] secondary_startup_64+0xa4/0xb0
This patch adds a check to prevent the panic.
Signed-off-by: He Zhe <zhe.he@windriver.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
a huge latency in the system because it does a while loop to free pages
without releasing the CPU (on non preempt kernels). In a case where there
are hundreds of thousands of pages to free it could actually cause a system
stall. A properly place cond_resched() solves this issue.
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Merge tag 'trace-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Steven writes:
"Vaibhav Nagarnaik found that modifying the ring buffer size could cause
a huge latency in the system because it does a while loop to free pages
without releasing the CPU (on non preempt kernels). In a case where there
are hundreds of thousands of pages to free it could actually cause a system
stall. A properly place cond_resched() solves this issue."
It has been pointed out to me many times that it is useful to be able to
switch off AUX records to save the bandwidth for records that actually
matter, for example, in AUX overwrite mode.
The usefulness of PERF_RECORD_AUX is in some of its flags, like the
TRUNCATED flag that tells the decoder where exactly gaps in the trace
are. The OVERWRITE flag, on the other hand will be set on every single
record in overwrite mode. However, a PERF_RECORD_AUX[flags=OVERWRITE] is
generated on every target task's sched_out, which over time adds up to a
lot of useless information.
If any folks out there have userspace that depends on a constant stream
of OVERWRITE records for a good reason, they'll have to let us know.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Link: http://lkml.kernel.org/r/20180404145323.28651-1-alexander.shishkin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Two new tls tests added in parallel in both net and net-next.
Used Stephen Rothwell's linux-next resolution.
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux spreads out the non managed interrupt across the possible target CPUs
to avoid vector space exhaustion.
Managed interrupts are treated differently, as for them the vectors are
reserved (with guarantee) when the interrupt descriptors are initialized.
When the interrupt is requested a real vector is assigned. The assignment
logic uses the first CPU in the affinity mask for assignment. If the
interrupt has more than one CPU in the affinity mask, which happens when a
multi queue device has less queues than CPUs, then doing the same search as
for non managed interrupts makes sense as it puts the interrupt on the
least interrupt plagued CPU. For single CPU affine vectors that's obviously
a NOOP.
Restructre the matrix allocation code so it does the 'best CPU' search, add
the sanity check for an empty affinity mask and adapt the call site in the
x86 vector management code.
[ tglx: Added the empty mask check to the core and improved change log ]
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180908175838.14450-2-dou_liyang@163.com
Linux finds the CPU which has the lowest vector allocation count to spread
out the non managed interrupts across the possible target CPUs, but does
not do so for managed interrupts.
Split out the CPU selection code into a helper function for reuse. No
functional change.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180908175838.14450-1-dou_liyang@163.com
Dave writes:
"Various fixes, all over the place:
1) OOB data generation fix in bluetooth, from Matias Karhumaa.
2) BPF BTF boundary calculation fix, from Martin KaFai Lau.
3) Don't bug on excessive frags, to be compatible in situations mixing
older and newer kernels on each end. From Juergen Gross.
4) Scheduling in RCU fix in hv_netvsc, from Stephen Hemminger.
5) Zero keying information in TLS layer before freeing copies
of them, from Sabrina Dubroca.
6) Fix NULL deref in act_sample, from Davide Caratti.
7) Orphan SKB before GRO in veth to prevent crashes with XDP,
from Toshiaki Makita.
8) Fix use after free in ip6_xmit, from Eric Dumazet.
9) Fix VF mac address regression in bnxt_en, from Micahel Chan.
10) Fix MSG_PEEK behavior in TLS layer, from Daniel Borkmann.
11) Programming adjustments to r8169 which fix not being to enter deep
sleep states on some machines, from Kai-Heng Feng and Hans de
Goede.
12) Fix DST_NOCOUNT flag handling for ipv6 routes, from Peter
Oskolkov."
* gitolite.kernel.org:/pub/scm/linux/kernel/git/davem/net: (45 commits)
net/ipv6: do not copy dst flags on rt init
qmi_wwan: set DTR for modems in forced USB2 mode
clk: x86: Stop marking clocks as CLK_IS_CRITICAL
r8169: Get and enable optional ether_clk clock
clk: x86: add "ether_clk" alias for Bay Trail / Cherry Trail
r8169: enable ASPM on RTL8106E
r8169: Align ASPM/CLKREQ setting function with vendor driver
Revert "kcm: remove any offset before parsing messages"
kcm: remove any offset before parsing messages
net: ethernet: Fix a unused function warning.
net: dsa: mv88e6xxx: Fix ATU Miss Violation
tls: fix currently broken MSG_PEEK behavior
hv_netvsc: pair VF based on serial number
PCI: hv: support reporting serial number as slot information
bnxt_en: Fix VF mac address regression.
ipv6: fix possible use-after-free in ip6_xmit()
net: hp100: fix always-true check for link up state
ARM: dts: at91: add new compatibility string for macb on sama5d3
net: macb: disable scatter-gather for macb on sama5d3
net: mvpp2: let phylink manage the carrier state
...
When reducing ring buffer size, pages are removed by scheduling a work
item on each CPU for the corresponding CPU ring buffer. After the pages
are removed from ring buffer linked list, the pages are free()d in a
tight loop. The loop does not give up CPU until all pages are removed.
In a worst case behavior, when lot of pages are to be freed, it can
cause system stall.
After the pages are removed from the list, the free() can happen while
the work is rescheduled. Call cond_resched() in the loop to prevent the
system hangup.
Link: http://lkml.kernel.org/r/20180907223129.71994-1-vnagarnaik@google.com
Cc: stable@vger.kernel.org
Fixes: 83f40318da ("ring-buffer: Make removal of ring buffer pages atomic")
Reported-by: Jason Behmer <jbehmer@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Daniel Borkmann says:
====================
pull-request: bpf 2018-09-16
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix end boundary calculation in BTF for the type section, from Martin.
2) Fix and revert subtraction of pointers that was accidentally allowed
for unprivileged programs, from Alexei.
3) Fix bpf_msg_pull_data() helper by using __GFP_COMP in order to avoid
a warning in linearizing sg pages into a single one for large allocs,
from Tushar.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
For readability and consistency with the other exports in
kernel/signal.c pair the exports of signal sending functions with
their functions, instead of having the exports in one big clump.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This function is static and it only has two callers. As
specific_send_sig_info is only called twice remembering what
specific_send_sig_info does when reading the code is difficutl and it
makes it hard to see which sending sending functions are equivalent to
which others.
So remove specific_send_sig_info to make the code easier to read.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Replace send_sig_info in zap_pid_ns_processes with
group_send_sig_info. This makes more sense as the entire process
group is being killed. More importantly this allows the kill of those
processes with PIDTYPE_MAX to indicate all of the process in the pid
namespace are being signaled. This is needed for fork to detect when
signals are sent to a group of processes.
Admittedly fork has another case to catch SIGKILL but the principle remains
that it is desirable to know when a group of processes is being signaled.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull scheduler fixes from Ingo Molnar:
"Misc fixes: various scheduler metrics corner case fixes, a
sched_features deadlock fix, and a topology fix for certain NUMA
systems"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix kernel-doc notation warning
sched/fair: Fix load_balance redo for !imbalance
sched/fair: Fix scale_rt_capacity() for SMT
sched/fair: Fix vruntime_normalized() for remote non-migration wakeup
sched/pelt: Fix update_blocked_averages() for RT and DL classes
sched/topology: Set correct NUMA topology type
sched/debug: Fix potential deadlock when writing to sched_features
Adds a hook for programs of type BPF_PROG_TYPE_FLOW_DISSECTOR and
attach type BPF_FLOW_DISSECTOR that is executed in the flow dissector
path. The BPF program is per-network namespace.
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'printk-for-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk fix from Petr Mladek:
"Revert a commit that caused "quiet", "debug", and "loglevel" early
parameters to be ignored for early boot messages"
* tag 'printk-for-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
Revert "printk: make sure to print log on console."
Subtraction of pointers was accidentally allowed for unpriv programs
by commit 82abbf8d2f. Revert that part of commit.
Fixes: 82abbf8d2f ("bpf: do not allow root to mangle valid pointers")
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The end boundary math for type section is incorrect in
btf_check_all_metas(). It just happens that hdr->type_off
is always 0 for now because there are only two sections
(type and string) and string section must be at the end (ensured
in btf_parse_str_sec).
However, type_off may not be 0 if a new section would be added later.
This patch fixes it.
Fixes: f80442a4cd ("bpf: btf: Change how section is supported in btf_header")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Instead of calling BUG_ON(), if we find a kprobe in use on free kprobe
list, just remove it from the list and keep it on kprobe hash list
as same as other in-use kprobes.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666126882.21306.10738207224288507996.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Make reuse_unused_kprobe() to return error code if
it fails to reuse unused kprobe for optprobe instead
of calling BUG_ON().
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666124040.21306.14150398706331307654.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since reuse_unused_kprobe() is called when the given kprobe
is unused, checking it inside again with BUG_ON() is
pointless. Remove it.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666121154.21306.17540752948574483565.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Before calling add_new_kprobe(), aggr_probe's GONE
flag and kprobe GONE flag are cleared. We don't need
to worry about that flag at this point.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666118298.21306.4915366706875652652.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
All aggr_probes at this line are already disarmed by
disable_kprobe() or checked by kprobe_disarmed().
So this BUG_ON() is pointless, remove it.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666115463.21306.8799008438116029806.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Added bpffs pretty print for program array map. For a particular
array index, if the program array points to a valid program,
the "<index>: <prog_id>" will be printed out like
0: 6
which means bpf program with id "6" is installed at index "0".
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There are no more users of SEND_SIG_FORCED so it may be safely removed.
Remove the definition of SEND_SIG_FORCED, it's use in is_si_special,
it's use in TP_STORE_SIGINFO, and it's use in __send_signal as without
any users the uses of SEND_SIG_FORCED are now unncessary.
This makes the code simpler, easier to understand and use. Users of
signal sending functions now no longer need to ask themselves do I
need to use SEND_SIG_FORCED.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that siginfo is never allocated for SIGKILL and SIGSTOP there is
no difference between SEND_SIG_PRIV and SEND_SIG_FORCED for SIGKILL
and SIGSTOP. This makes SEND_SIG_FORCED unnecessary and redundant in
the presence of SIGKILL and SIGSTOP. Therefore change users of
SEND_SIG_FORCED that are sending SIGKILL or SIGSTOP to use
SEND_SIG_PRIV instead.
This removes the last users of SEND_SIG_FORCED.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The SIGKILL and SIGSTOP signals are never delivered to userspace so
queued siginfo for these signals can never be observed. Therefore
remove the chance of failure by never even attempting to allocate
siginfo in those cases.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Today kernel threads never dequeue siginfo so it is pointless to
enqueue siginfo for them. The usb gadget mass storage driver goes
one farther and uses SEND_SIG_FORCED to guarantee that no siginfo is
even enqueued.
Generalize the optimization of the usb mass storage driver and never
perform an unnecessary allocation when delivering signals to kthreads.
Switch the mass storage driver from sending signals with
SEND_SIG_FORCED to SEND_SIG_PRIV. As using SEND_SIG_FORCED is now
unnecessary.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Instead of playing whack-a-mole and changing SEND_SIG_PRIV to
SEND_SIG_FORCED throughout the kernel to ensure a pid namespace init
gets signals sent by the kernel, stop allowing a pid namespace init to
ignore SIGKILL or SIGSTOP sent by the kernel. A pid namespace init is
only supposed to be able to ignore signals sent from itself and
children with SIG_DFL.
Fixes: 921cf9f630 ("signals: protect cinit from unblocked SIG_DFL signals")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
For userspace to tell the difference between a random signal and an
exception, the exception must include siginfo information.
Using SEND_SIG_FORCED for SIGILL is thus wrong, and it will result
in userspace seeing si_code == SI_USER (like a random signal) instead
of si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.
Therefore replace force_sig_info(SIGILL, SEND_SIG_FORCE, current)
with force_sig(SIG_ILL, current) which gets this right and is
shorter and easier to type.
Fixes: 014940bad8 ("uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails")
Fixes: 0b5256c7f1 ("uprobes: Send SIGILL if handle_trampoline() fails")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
If the first process started (aka /sbin/init) receives a SIGKILL it
will panic the system if it is delivered. Making the system unusable
and undebugable. It isn't much better if the first process started
receives SIGSTOP.
So always ignore SIGSTOP and SIGKILL sent to init.
This is done in a separate clause in sig_task_ignored as force_sig_info
can clear SIG_UNKILLABLE and this protection should work even then.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Anybody trying to assert the cpu_hotplug_lock is held (lockdep_assert_cpus_held())
from AP callbacks will fail, because the lock is held by the BP.
Stick in an explicit annotation in cpuhp_thread_fun() to make this work.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-tip-commits@vger.kernel.org
Fixes: cb538267ea ("jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations")
Link: http://lkml.kernel.org/r/20180911095127.GT24082@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Export pm_power_off_prepare. It is needed to implement power off on
Freescale/NXP iMX6 based boards with external power management
integrated circuit (PMIC).
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This reverts commit 375899cddc.
The visibility of early messages did not longer take into account
"quiet", "debug", and "loglevel" early parameters.
It would be possible to invalidate and recompute LOG_NOCONS flag
for the affected messages. But it would be hairy.
Instead this patch just reverts the problematic commit. We could
come up with a better solution for the original problem. For example,
we could simplify the logic and just mark messages that should always
be visible or always invisible on the console.
Also this patch reverts the related build fix commit ffaa619af1
("printk: Fix warning about unused suppress_message_printing").
Finally, this patch does not put back the unused LOG_NOCONS flag.
Link: http://lkml.kernel.org/r/20180910145747.emvfzv4mzlk5dfqk@pathway.suse.cz
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Maninder Singh <maninder1.s@samsung.com>
Reported-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Merging v4.14.68 into v4.14-rt I tripped over a conflict in the
rtmutex.c code. There I found that we had:
#ifdef CONFIG_DEBUG_LOCK_ALLOC
[..]
#endif
#ifndef CONFIG_DEBUG_LOCK_ALLOC
[..]
#endif
Really this should be:
#ifdef CONFIG_DEBUG_LOCK_ALLOC
[..]
#else
[..]
#endif
This cleans up that logic.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Rosin <peda@axentia.se>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180910214638.55926030@vmware.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both kallsyms_num_syms and kallsyms_markers[] don't really need to use
unsigned long as their (base) types; unsigned int fully suffices.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Fix the following warnings:
kernel/sched/topology.c:10:15: warning: symbol 'sched_domains_tmpmask' was not declared. Should it be static?
kernel/sched/topology.c:11:15: warning: symbol 'sched_domains_tmpmask2' was not declared. Should it be static?
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1533299852-26941-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Perf can record user stack data in response to a synchronous request, such
as a tracepoint firing. If this happens under set_fs(KERNEL_DS), then we
end up reading user stack data using __copy_from_user_inatomic() under
set_fs(KERNEL_DS). I think this conflicts with the intention of using
set_fs(KERNEL_DS). And it is explicitly forbidden by hardware on ARM64
when both CONFIG_ARM64_UAO and CONFIG_ARM64_PAN are used.
So fix this by forcing USER_DS when recording user stack data.
Signed-off-by: Yabin Cui <yabinc@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 88b0193d94 ("perf/callchain: Force USER_DS when invoking perf_callchain_user()")
Link: http://lkml.kernel.org/r/20180823225935.27035-1-yabinc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Trivial fix to spelling mistake in pr_err() error message
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/20180824112235.8842-1-colin.king@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit:
c3bc8fd637 ("tracing: Centralize preemptirq tracepoints and unify their usage")
added the inclusion of <trace/events/preemptirq.h>.
liblockdep doesn't have a stub version of that header so now fails to build.
However, commit:
bff1b208a5 ("tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"")
removed the use of functions declared in that header. So delete the #include.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <alexander.levin@verizon.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: bff1b208a5 ("tracing: Partial revert of "tracing: Centralize ...")
Fixes: c3bc8fd637 ("tracing: Centralize preemptirq tracepoints ...")
Link: http://lkml.kernel.org/r/20180828203315.GD18030@decadent.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For debug purposes it would be nice to see which tasks
caused a suspend abort, i.e. which tasks were still
in the process of freezing when a wakeup event occurred.
This patch adds the info to pm_debug_messages.
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, when a reader acquires a lock, it only sets the
RWSEM_READER_OWNED bit in the owner field. The other bits are simply
not used. When debugging hanging cases involving rwsems and readers,
the owner value does not provide much useful information at all.
This patch modifies the current behavior to always store the task_struct
pointer of the last rwsem-acquiring reader in a reader-owned rwsem. This
may be useful in debugging rwsem hanging cases especially if only one
reader is involved. However, the task in the owner field may not the
real owner or one of the real owners at all when the owner value is
examined, for example, in a crash dump. So it is just an additional
hint about the past history.
If CONFIG_DEBUG_RWSEMS=y is enabled, the owner field will be checked at
unlock time too to make sure the task pointer value is valid. That does
have a slight performance cost and so is only enabled as part of that
debug option.
From the performance point of view, it is expected that the changes
shouldn't have any noticeable performance impact. A rwsem microbenchmark
(with 48 worker threads and 1:1 reader/writer ratio) was ran on a
2-socket 24-core 48-thread Haswell system. The locking rates on a
4.19-rc1 based kernel were as follows:
1) Unpatched kernel: 543.3 kops/s
2) Patched kernel: 549.2 kops/s
3) Patched kernel (CONFIG_DEBUG_RWSEMS on): 546.6 kops/s
There was actually a slight increase in performance (1.1%) in this
particular case. Maybe it was caused by the elimination of a branch or
just a testing noise. Turning on the CONFIG_DEBUG_RWSEMS option also
had less than the expected impact on performance.
The least significant 2 bits of the owner value are now used to designate
the rwsem is readers owned and the owners are anonymous.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1536265114-10842-1-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
nr_running in struct numa_stats is not used anywhere in the code.
Remove it.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1535548752-4434-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With:
commit 2d4056fafa ("sched/numa: Remove numa_has_capacity()")
the local variables 'smt', 'cpus' and 'capacity' and their results are not used
anymore in numa_has_capacity()
Remove this unused code.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1535548752-4434-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
LLVM has a warning that tags expressions like:
if (foo && non-bool-const)
This pattern triggers for CONFIG_SCHED_DEBUG=n where sched_feat() ends
up being whatever bit we select. Avoid the warning with an explicit
cast to bool.
Reported-by: Philipp Klocke <philipp97kl@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The 'prefer sibling' sched_domain flag is intended to encourage
spreading tasks to sibling sched_domain to take advantage of more caches
and core for SMT systems. It has recently been changed to be on all
non-NUMA topology level. However, spreading across domains with CPU
capacity asymmetry isn't desirable, e.g. spreading from high capacity to
low capacity CPUs even if high capacity CPUs aren't overutilized might
give access to more cache but the CPU will be slower and possibly lead
to worse overall throughput.
To prevent this, we need to remove SD_PREFER_SIBLING on the sched_domain
level immediately below SD_ASYM_CPUCAPACITY.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-13-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When lower capacity CPUs are load balancing and considering to pull
something from a higher capacity group, we should not pull tasks from a
CPU with only one task running as this is guaranteed to impede progress
for that task. If there is more than one task running, load balance in
the higher capacity group would have already made any possible moves to
resolve imbalance and we should make better use of system compute
capacity by moving a task if we still have more than one running.
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-11-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Idle balance is a great opportunity to pull a misfit task. However,
there are scenarios where misfit tasks are present but idle balance is
prevented by the overload flag.
A good example of this is a workload of n identical tasks. Let's suppose
we have a 2+2 Arm big.LITTLE system. We then spawn 4 fairly
CPU-intensive tasks - for the sake of simplicity let's say they are just
CPU hogs, even when running on big CPUs.
They are identical tasks, so on an SMP system they should all end at
(roughly) the same time. However, in our case the LITTLE CPUs are less
performing than the big CPUs, so tasks running on the LITTLEs will have
a longer completion time.
This means that the big CPUs will complete their work earlier, at which
point they should pull the tasks from the LITTLEs. What we want to
happen is summarized as follows:
a,b,c,d are our CPU-hogging tasks _ signifies idling
LITTLE_0 | a a a a _ _
LITTLE_1 | b b b b _ _
---------|-------------
big_0 | c c c c a a
big_1 | d d d d b b
^
^
Tasks end on the big CPUs, idle balance happens
and the misfit tasks are pulled straight away
This however won't happen, because currently the overload flag is only
set when there is any CPU that has more than one runnable task - which
may very well not be the case here if our CPU-hogging workload is all
there is to run.
As such, this commit sets the overload flag in update_sg_lb_stats when
a group is flagged as having a misfit task.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-10-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This variable can be read and set locklessly within update_sd_lb_stats().
As such, READ/WRITE_ONCE() are added to make sure nothing terribly wrong
can happen because of the compiler.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-9-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
sizeof(_Bool) is implementation defined, so let's just go with 'int' as
is done for other structures e.g. sched_domain_shared->has_idle_cores.
The local 'overload' variable used in update_sd_lb_stats can remain
bool, as it won't impact any struct layout and can be assigned to the
root_domain field.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-8-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This variable is entirely local to update_sd_lb_stats, so we can
safely change its type and slightly clean up its initialisation.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-7-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There already are a few conditions in nohz_kick_needed() to ensure
a nohz kick is triggered, but they are not enough for some misfit
task scenarios. Excluding asym packing, those are:
- rq->nr_running >=2: Not relevant here because we are running a
misfit task, it needs to be migrated regardless and potentially through
active balance.
- sds->nr_busy_cpus > 1: If there is only the misfit task being run
on a group of low capacity CPUs, this will be evaluated to False.
- rq->cfs.h_nr_running >=1 && check_cpu_capacity(): Not relevant here,
misfit task needs to be migrated regardless of rt/IRQ pressure
As such, this commit adds an rq->misfit_task_load condition to trigger a
nohz kick.
The idea to kick a nohz balance for misfit tasks originally came from
Leo Yan <leo.yan@linaro.org>, and a similar patch was submitted for
the Android Common Kernel - see:
https://lists.linaro.org/pipermail/eas-dev/2016-September/000551.html
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-6-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On asymmetric CPU capacity systems load intensive tasks can end up on
CPUs that don't suit their compute demand. In this scenarios 'misfit'
tasks should be migrated to CPUs with higher compute capacity to ensure
better throughput. group_misfit_task indicates this scenario, but tweaks
to the load-balance code are needed to make the migrations happen.
Misfit balancing only makes sense between a source group of lower
per-CPU capacity and destination group of higher compute capacity.
Otherwise, misfit balancing is ignored. group_misfit_task has lowest
priority so any imbalance due to overload is dealt with first.
The modifications are:
1. Only pick a group containing misfit tasks as the busiest group if the
destination group has higher capacity and has spare capacity.
2. When the busiest group is a 'misfit' group, skip the usual average
load and group capacity checks.
3. Set the imbalance for 'misfit' balancing sufficiently high for a task
to be pulled ignoring average load.
4. Pick the CPU with the highest misfit load as the source CPU.
5. If the misfit task is alone on the source CPU, go for active
balancing.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-5-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current sg->min_capacity tracks the lowest per-CPU compute capacity
available in the sched_group when rt/irq pressure is taken into account.
Minimum capacity isn't the ideal metric for tracking if a sched_group
needs offloading to another sched_group for some scenarios, e.g. a
sched_group with multiple CPUs if only one is under heavy pressure.
Tracking maximum capacity isn't perfect either but a better choice for
some situations as it indicates that the sched_group definitely compute
capacity constrained either due to rt/irq pressure on all CPUs or
asymmetric CPU capacities (e.g. big.LITTLE).
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-4-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
To maximize throughput in systems with asymmetric CPU capacities (e.g.
ARM big.LITTLE) load-balancing has to consider task and CPU utilization
as well as per-CPU compute capacity when load-balancing in addition to
the current average load based load-balancing policy. Tasks with high
utilization that are scheduled on a lower capacity CPU need to be
identified and migrated to a higher capacity CPU if possible to maximize
throughput.
To implement this additional policy an additional group_type
(load-balance scenario) is added: 'group_misfit_task'. This represents
scenarios where a sched_group has one or more tasks that are not
suitable for its per-CPU capacity. 'group_misfit_task' is only considered
if the system is not overloaded or imbalanced ('group_imbalanced' or
'group_overloaded').
Identifying misfit tasks requires the rq lock to be held. To avoid
taking remote rq locks to examine source sched_groups for misfit tasks,
each CPU is responsible for tracking misfit tasks themselves and update
the rq->misfit_task flag. This means checking task utilization when
tasks are scheduled and on sched_tick.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-3-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The existing asymmetric CPU capacity code should cause minimal overhead
for others. Putting it behind a static_key, it has been done for SMT
optimizations, would make it easier to extend and improve without
causing harm to others moving forward.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-2-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The SD_ASYM_CPUCAPACITY sched_domain flag is supposed to mark the
sched_domain in the hierarchy where all CPU capacities are visible for
any CPU's point of view on asymmetric CPU capacity systems. The
scheduler can then take to take capacity asymmetry into account when
balancing at this level. It also serves as an indicator for how wide
task placement heuristics have to search to consider all available CPU
capacities as asymmetric systems might often appear symmetric at
smallest level(s) of the sched_domain hierarchy.
The flag has been around for while but so far only been set by
out-of-tree code in Android kernels. One solution is to let each
architecture provide the flag through a custom sched_domain topology
array and associated mask and flag functions. However,
SD_ASYM_CPUCAPACITY is special in the sense that it depends on the
capacity and presence of all CPUs in the system, i.e. when hotplugging
all CPUs out except those with one particular CPU capacity the flag
should disappear even if the sched_domains don't collapse. Similarly,
the flag is affected by cpusets where load-balancing is turned off.
Detecting when the flags should be set therefore depends not only on
topology information but also the cpuset configuration and hotplug
state. The arch code doesn't have easy access to the cpuset
configuration.
Instead, this patch implements the flag detection in generic code where
cpusets and hotplug state is already taken care of. All the arch is
responsible for is to implement arch_scale_cpu_capacity() and force a
full rebuild of the sched_domain hierarchy if capacities are updated,
e.g. later in the boot process when cpufreq has initialized.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1532093554-30504-2-git-send-email-morten.rasmussen@arm.com
[ Fixed 'CPU' capitalization. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix kernel-doc warning for missing 'flags' parameter description:
../kernel/sched/fair.c:3371: warning: Function parameter or member 'flags' not described in 'attach_entity_load_avg'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: ea14b57e8a ("sched/cpufreq: Provide migration hint")
Link: http://lkml.kernel.org/r/cdda0d42-880d-4229-a9f7-5899c977a063@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It was discovered that a constant stream of readers with occassional
writers pounding on a rwsem may cause many of the readers to enter the
slowpath unnecessarily thus increasing latency and lowering performance.
In the current code, a reader entering the slowpath critical section
will unconditionally set the WAITING_BIAS, if not set yet, and clear
its active count even if no one is in the wait queue and no writer
is present. This causes some incoming readers to observe the presence
of waiters in the wait queue and hence have to go into the slowpath
themselves.
With sufficient numbers of readers and a relatively short lock hold time,
the WAITING_BIAS may be repeatedly turned on and off and a substantial
portion of the readers will go into the slowpath sustaining a rather
long queue in the wait queue spinlock and repeated WAITING_BIAS on/off
cycle until the logjam is broken opportunistically.
To avoid this situation from happening, an additional check is added to
detect the special case that the reader in the critical section is the
only one in the wait queue and no writer is present. When that happens,
it can just exit the slowpath and return immediately as its active count
has already been set in the lock. Other incoming readers won't observe
the presence of waiters and so will not be forced into the slowpath.
The issue was found in a customer site where they had an application
that pounded on the pread64 syscalls heavily on an XFS filesystem. The
application was run in a recent 4-socket boxes with a lot of CPUs. They
saw significant spinlock contention in the rwsem_down_read_failed() call.
With this patch applied, the system CPU usage went down from 85% to 57%,
and the spinlock contention in the pread64 syscalls was gone.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1532459425-19204-1-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Weirdly we seem to have forgotten this...
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It can happen that load_balance() finds a busiest group and then a
busiest rq but the calculated imbalance is in fact 0.
In such situation, detach_tasks() returns immediately and lets the
flag LBF_ALL_PINNED set. The busiest CPU is then wrongly assumed to
have pinned tasks and removed from the load balance mask. then, we
redo a load balance without the busiest CPU. This creates wrong load
balance situation and generates wrong task migration.
If the calculated imbalance is 0, it's useless to try to find a
busiest rq as no task will be migrated and we can return immediately.
This situation can happen with heterogeneous system or smp system when
RT tasks are decreasing the capacity of some CPUs.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: jhugo@codeaurora.org
Link: http://lkml.kernel.org/r/1536306664-29827-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since commit:
523e979d31 ("sched/core: Use PELT for scale_rt_capacity()")
scale_rt_capacity() returns the remaining capacity and not a scale factor
to apply on cpu_capacity_orig. arch_scale_cpu() is directly called by
scale_rt_capacity() so we must take the sched_domain argument.
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 523e979d31 ("sched/core: Use PELT for scale_rt_capacity()")
Link: http://lkml.kernel.org/r/20180904093626.GA23936@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a task which previously ran on a given CPU is remotely queued to
wake up on that same CPU, there is a period where the task's state is
TASK_WAKING and its vruntime is not normalized. This is not accounted
for in vruntime_normalized() which will cause an error in the task's
vruntime if it is switched from the fair class during this time.
For example if it is boosted to RT priority via rt_mutex_setprio(),
rq->min_vruntime will not be subtracted from the task's vruntime but
it will be added again when the task returns to the fair class. The
task's vruntime will have been erroneously doubled and the effective
priority of the task will be reduced.
Note this will also lead to inflation of all vruntimes since the doubled
vruntime value will become the rq's min_vruntime when other tasks leave
the rq. This leads to repeated doubling of the vruntime and priority
penalty.
Fix this by recognizing a WAKING task's vruntime as normalized only if
sched_remote_wakeup is true. This indicates a migration, in which case
the vruntime would have been normalized in migrate_task_rq_fair().
Based on a similar patch from John Dias <joaodias@google.com>.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Steve Muckle <smuckle@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Redpath <Chris.Redpath@arm.com>
Cc: John Dias <joaodias@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel de Dios <migueldedios@google.com>
Cc: Morten Rasmussen <Morten.Rasmussen@arm.com>
Cc: Patrick Bellasi <Patrick.Bellasi@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: kernel-team@android.com
Fixes: b5179ac70d ("sched/fair: Prepare to fix fairness problems on migration")
Link: http://lkml.kernel.org/r/20180831224217.169476-1-smuckle@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
update_blocked_averages() is called to periodiccally decay the stalled load
of idle CPUs and to sync all loads before running load balance.
When cfs rq is idle, it trigs a load balance during pick_next_task_fair()
in order to potentially pull tasks and to use this newly idle CPU. This
load balance happens whereas prev task from another class has not been put
and its utilization updated yet. This may lead to wrongly account running
time as idle time for RT or DL classes.
Test that no RT or DL task is running when updating their utilization in
update_blocked_averages().
We still update RT and DL utilization instead of simply skipping them to
make sure that all metrics are synced when used during load balance.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 371bf42732 ("sched/rt: Add rt_rq utilization tracking")
Fixes: 3727e0e163 ("sched/dl: Add dl_rq utilization tracking")
Link: http://lkml.kernel.org/r/1535728975-22799-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With the following commit:
051f3ca02e ("sched/topology: Introduce NUMA identity node sched domain")
the scheduler introduced a new NUMA level. However this leads to the NUMA topology
on 2 node systems to not be marked as NUMA_DIRECT anymore.
After this commit, it gets reported as NUMA_BACKPLANE, because
sched_domains_numa_level is now 2 on 2 node systems.
Fix this by allowing setting systems that have up to 2 NUMA levels as
NUMA_DIRECT.
While here remove code that assumes that level can be 0.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andre Wild <wild@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Fixes: 051f3ca02e "Introduce NUMA identity node sched domain"
Link: http://lkml.kernel.org/r/1533920419-17410-1-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following commit:
08295b3b5b ("Implement an algorithm choice for Wound-Wait mutexes")
introduced a reference in the documentation to a function that was
removed in an earlier commit.
It also forgot to remove a call to debug_mutex_add_waiter() which is now
unconditionally called by __mutex_add_waiter().
Fix those bugs.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Fixes: 08295b3b5b ("Implement an algorithm choice for Wound-Wait mutexes")
Link: http://lkml.kernel.org/r/20180903140708.2401-1-thellstrom@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Kernel:
- Modify breakpoint fixes (Jiri Olsa)
perf annotate:
- Fix parsing aarch64 branch instructions after objdump update (Kim Phillips)
- Fix parsing indirect calls in 'perf annotate' (Martin Liška)
perf probe:
- Ignore SyS symbols irrespective of endianness on PowerPC (Sandipan Das)
perf trace:
- Fix include path for asm-generic/unistd.h on arm64 (Kim Phillips)
Core libraries:
- Fix potential null pointer dereference in perf_evsel__new_idx() (Hisao Tanabe)
- Use fixed size string for comms instead of scanf("%m"), that is
not present in the bionic libc and leads to a crash (Chris Phlipot)
- Fix bad memory access in trace info on 32-bit systems, we were reading
8 bytes from a 4-byte long variable when saving the command line in the
perf.data file. (Chris Phlipot)
Build system:
- Streamline bpf examples and headers installation, clarifying
some install messages. (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-urgent-for-mingo-4.19-20180903' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
Kernel:
- Modify breakpoint fixes (Jiri Olsa)
perf annotate:
- Fix parsing aarch64 branch instructions after objdump update (Kim Phillips)
- Fix parsing indirect calls in 'perf annotate' (Martin Liška)
perf probe:
- Ignore SyS symbols irrespective of endianness on PowerPC (Sandipan Das)
perf trace:
- Fix include path for asm-generic/unistd.h on arm64 (Kim Phillips)
Core libraries:
- Fix potential null pointer dereference in perf_evsel__new_idx() (Hisao Tanabe)
- Use fixed size string for comms instead of scanf("%m"), that is
not present in the bionic libc and leads to a crash (Chris Phlipot)
- Fix bad memory access in trace info on 32-bit systems, we were reading
8 bytes from a 4-byte long variable when saving the command line in the
perf.data file. (Chris Phlipot)
Build system:
- Streamline bpf examples and headers installation, clarifying
some install messages. (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timekeeping fixes from Thomas Gleixner:
"Two fixes for timekeeping:
- Revert to the previous kthread based update, which is unfortunately
required due to lock ordering issues. The removal caused boot
failures on old Core2 machines. Add a proper comment why the thread
needs to stay to prevent accidental removal in the future.
- Fix a silly typo in a function declaration"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource: Revert "Remove kthread"
timekeeping: Fix declaration of read_persistent_wall_and_boot_offset()
Pull cpu hotplug fixes from Thomas Gleixner:
"Two fixes for the hotplug state machine code:
- Move the misplaces smb() in the hotplug thread function to the
proper place, otherwise a half update control struct could be
observed
- Prevent state corruption on error rollback, which causes the state
to advance by one and as a consequence skip it in the bringup
sequence"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Prevent state corruption on error rollback
cpu/hotplug: Adjust misplaced smb() in cpuhp_thread_fun()
This goes through a lot of hooks just to call arch_teardown_dma_ops.
Replace it with a direct call instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
There is no good reason for this indirection given that the method
always exists.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
I turns out that the silly spawn kthread from worker was actually needed.
clocksource_watchdog_kthread() cannot be called directly from
clocksource_watchdog_work(), because clocksource_select() calls
timekeeping_notify() which uses stop_machine(). One cannot use
stop_machine() from a workqueue() due lock inversions wrt CPU hotplug.
Revert the patch but add a comment that explain why we jump through such
apparently silly hoops.
Fixes: 7197e77abc ("clocksource: Remove kthread")
Reported-by: Siegfried Metz <frame@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Tested-by: Kevin Shanahan <kevin@shanahan.id.au>
Tested-by: viktor_jaegerskuepper@freenet.de
Tested-by: Siegfried Metz <frame@mailbox.org>
Cc: rafael.j.wysocki@intel.com
Cc: len.brown@intel.com
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: bjorn.andersson@linaro.org
Link: https://lkml.kernel.org/r/20180905084158.GR24124@hirez.programming.kicks-ass.net
WARN_ON() already contains an unlikely(), so it's not necessary to wrap it
into another.
Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: linux-security-module@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: James Morris <james.morris@microsoft.com>
- The first one is a side effect caused by using SRCU for rcuidle
tracepoints. It seems that the perf was depending on the rcuidle
tracepoints to make RCU watch when it wasn't. The real fix will
bet to have perf use SRCU instead of depending on RCU watching,
but that can't be done until SRCU is safe to use in NMI context
(Paul's working on that).
- The second bug fix is for a bug that's been periodically making
my tests fail randomly for some time. I haven't had time to track
it down, but finally have. It has to do with stressing NMIs (via perf)
while enabling or disabling ftrace function handling with lockdep
enabled. If an interrupt happens and just as it returns, it sets
lockdep back to "interrupts enabled" but before it returns an NMI
is triggered, and if this happens while printk_nmi_enter has a
breakpoint attached to it (because ftrace is converting it to or from
nop to call fentry), the breakpoint trap also calls into lockdep,
and since returning from the NMI to a interrupt handler, interrupts
were disabled when the NMI went off, lockdep keeps its state as
interrupts disabled when it returns back from the interrupt handler
where interrupts are enabled. This causes lockdep_assert_irqs_enabled()
to trigger a false positive.
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Merge tag 'trace-v4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"This fixes two annoying bugs:
- The first one is a side effect caused by using SRCU for rcuidle
tracepoints. It seems that the perf was depending on the rcuidle
tracepoints to make RCU watch when it wasn't.
The real fix will be to have perf use SRCU instead of depending on
RCU watching, but that can't be done until SRCU is safe to use in
NMI context (Paul's working on that).
- The second bug fix is for a bug that's been periodically making my
tests fail randomly for some time. I haven't had time to track it
down, but finally have. It has to do with stressing NMIs (via perf)
while enabling or disabling ftrace function handling with lockdep
enabled.
If an interrupt happens and just as it returns, it sets lockdep
back to "interrupts enabled" but before it returns an NMI is
triggered, and if this happens while printk_nmi_enter has a
breakpoint attached to it (because ftrace is converting it to or
from nop to call fentry), the breakpoint trap also calls into
lockdep, and since returning from the NMI to a interrupt handler,
interrupts were disabled when the NMI went off, lockdep keeps its
state as interrupts disabled when it returns back from the
interrupt handler where interrupts are enabled.
This causes lockdep_assert_irqs_enabled() to trigger a false
positive"
* tag 'trace-v4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
printk/tracing: Do not trace printk_nmi_enter()
tracing: Add back in rcu_irq_enter/exit_irqson() for rcuidle tracepoints
I hit the following splat in my tests:
------------[ cut here ]------------
IRQs not enabled as expected
WARNING: CPU: 3 PID: 0 at kernel/time/tick-sched.c:982 tick_nohz_idle_enter+0x44/0x8c
Modules linked in: ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables ipv6
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.19.0-rc2-test+ #2
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
EIP: tick_nohz_idle_enter+0x44/0x8c
Code: ec 05 00 00 00 75 26 83 b8 c0 05 00 00 00 75 1d 80 3d d0 36 3e c1 00
75 14 68 94 63 12 c1 c6 05 d0 36 3e c1 01 e8 04 ee f8 ff <0f> 0b 58 fa bb a0
e5 66 c1 e8 25 0f 04 00 64 03 1d 28 31 52 c1 8b
EAX: 0000001c EBX: f26e7f8c ECX: 00000006 EDX: 00000007
ESI: f26dd1c0 EDI: 00000000 EBP: f26e7f40 ESP: f26e7f38
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010296
CR0: 80050033 CR2: 0813c6b0 CR3: 2f342000 CR4: 001406f0
Call Trace:
do_idle+0x33/0x202
cpu_startup_entry+0x61/0x63
start_secondary+0x18e/0x1ed
startup_32_smp+0x164/0x168
irq event stamp: 18773830
hardirqs last enabled at (18773829): [<c040150c>] trace_hardirqs_on_thunk+0xc/0x10
hardirqs last disabled at (18773830): [<c040151c>] trace_hardirqs_off_thunk+0xc/0x10
softirqs last enabled at (18773824): [<c0ddaa6f>] __do_softirq+0x25f/0x2bf
softirqs last disabled at (18773767): [<c0416bbe>] call_on_stack+0x45/0x4b
---[ end trace b7c64aa79e17954a ]---
After a bit of debugging, I found what was happening. This would trigger
when performing "perf" with a high NMI interrupt rate, while enabling and
disabling function tracer. Ftrace uses breakpoints to convert the nops at
the start of functions to calls to the function trampolines. The breakpoint
traps disable interrupts and this makes calls into lockdep via the
trace_hardirqs_off_thunk in the entry.S code. What happens is the following:
do_idle {
[interrupts enabled]
<interrupt> [interrupts disabled]
TRACE_IRQS_OFF [lockdep says irqs off]
[...]
TRACE_IRQS_IRET
test if pt_regs say return to interrupts enabled [yes]
TRACE_IRQS_ON [lockdep says irqs are on]
<nmi>
nmi_enter() {
printk_nmi_enter() [traced by ftrace]
[ hit ftrace breakpoint ]
<breakpoint exception>
TRACE_IRQS_OFF [lockdep says irqs off]
[...]
TRACE_IRQS_IRET [return from breakpoint]
test if pt_regs say interrupts enabled [no]
[iret back to interrupt]
[iret back to code]
tick_nohz_idle_enter() {
lockdep_assert_irqs_enabled() [lockdep say no!]
Although interrupts are indeed enabled, lockdep thinks it is not, and since
we now do asserts via lockdep, it gives a false warning. The issue here is
that printk_nmi_enter() is called before lockdep_off(), which disables
lockdep (for this reason) in NMIs. By simply not allowing ftrace to see
printk_nmi_enter() (via notrace annotation) we keep lockdep from getting
confused.
Cc: stable@vger.kernel.org
Fixes: 42a0bb3f71 ("printk/nmi: generic solution for safe printk in NMI")
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When a teardown callback fails, the CPU hotplug code brings the CPU back to
the previous state. The previous state becomes the new target state. The
rollback happens in undo_cpu_down() which increments the state
unconditionally even if the state is already the same as the target.
As a consequence the next CPU hotplug operation will start at the wrong
state. This is easily to observe when __cpu_disable() fails.
Prevent the unconditional undo by checking the state vs. target before
incrementing state and fix up the consequently wrong conditional in the
unplug code which handles the failure of the final CPU take down on the
control CPU side.
Fixes: 4dddfb5faa ("smp/hotplug: Rewrite AP state machine core")
Reported-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: josh@joshtriplett.org
Cc: peterz@infradead.org
Cc: jiangshanlai@gmail.com
Cc: dzickus@redhat.com
Cc: brendan.jackman@arm.com
Cc: malat@debian.org
Cc: sramana@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1809051419580.1416@nanos.tec.linutronix.de
----
Edward Cree says:
In check_mem_access(), for the PTR_TO_CTX case, after check_ctx_access()
has supplied a reg_type, the other members of the register state are set
appropriately. Previously reg.range was set to 0, but as it is in a
union with reg.map_ptr, which is larger, upper bytes of the latter were
left in place. This then caused the memcmp() in regsafe() to fail,
preventing some branches from being pruned (and occasionally causing the
same program to take a varying number of processed insns on repeated
verifier runs).
Fix the instability by clearing bpf_reg_state in __mark_reg_[un]known()
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Debugged-by: Edward Cree <ecree@solarflare.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Merge misc fixes from Andrew Morton:
"17 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
nilfs2: convert to SPDX license tags
drivers/dax/device.c: convert variable to vm_fault_t type
lib/Kconfig.debug: fix three typos in help text
checkpatch: add __ro_after_init to known $Attribute
mm: fix BUG_ON() in vmf_insert_pfn_pud() from VM_MIXEDMAP removal
uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name
memory_hotplug: fix kernel_panic on offline page processing
checkpatch: add optional static const to blank line declarations test
ipc/shm: properly return EIDRM in shm_lock()
mm/hugetlb: filter out hugetlb pages if HUGEPAGE migration is not supported.
mm/util.c: improve kvfree() kerneldoc
tools/vm/page-types.c: fix "defined but not used" warning
tools/vm/slabinfo.c: fix sign-compare warning
kmemleak: always register debugfs file
mm: respect arch_dup_mmap() return value
mm, oom: fix missing tlb_finish_mmu() in __oom_reap_task_mm().
mm: memcontrol: print proper OOM header when no eligible victim left
Commit d70f2a14b7 ("include/linux/sched/mm.h: uninline mmdrop_async(),
etc") ignored the return value of arch_dup_mmap(). As a result, on x86,
a failure to duplicate the LDT (e.g. due to memory allocation error)
would leave the duplicated memory mapping in an inconsistent state.
Fix by using the return value, as it was before the change.
Link: http://lkml.kernel.org/r/20180823051229.211856-1-namit@vmware.com
Fixes: d70f2a14b7 ("include/linux/sched/mm.h: uninline mmdrop_async(), etc")
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking fixes from David Miller:
1) Must perform TXQ teardown before unregistering interfaces in
mac80211, from Toke Høiland-Jørgensen.
2) Don't allow creating mac80211_hwsim with less than one channel, from
Johannes Berg.
3) Division by zero in cfg80211, fix from Johannes Berg.
4) Fix endian issue in tipc, from Haiqing Bai.
5) BPF sockmap use-after-free fixes from Daniel Borkmann.
6) Spectre-v1 in mac80211_hwsim, from Jinbum Park.
7) Missing rhashtable_walk_exit() in tipc, from Cong Wang.
8) Revert kvzalloc() conversion of AF_PACKET, it breaks mmap() when
kvzalloc() tries to use kmalloc() pages. From Eric Dumazet.
9) Fix deadlock in hv_netvsc, from Dexuan Cui.
10) Do not restart timewait timer on RST, from Florian Westphal.
11) Fix double lwstate refcount grab in ipv6, from Alexey Kodanev.
12) Unsolicit report count handling is off-by-one, fix from Hangbin Liu.
13) Sleep-in-atomic in cadence driver, from Jia-Ju Bai.
14) Respect ttl-inherit in ip6 tunnel driver, from Hangbin Liu.
15) Use-after-free in act_ife, fix from Cong Wang.
16) Missing hold to meta module in act_ife, from Vlad Buslov.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (91 commits)
net: phy: sfp: Handle unimplemented hwmon limits and alarms
net: sched: action_ife: take reference to meta module
act_ife: fix a potential use-after-free
net/mlx5: Fix SQ offset in QPs with small RQ
tipc: correct spelling errors for tipc_topsrv_queue_evt() comments
tipc: correct spelling errors for struct tipc_bc_base's comment
bnxt_en: Do not adjust max_cp_rings by the ones used by RDMA.
bnxt_en: Clean up unused functions.
bnxt_en: Fix firmware signaled resource change logic in open.
sctp: not traverse asoc trans list if non-ipv6 trans exists for ipv6_flowlabel
sctp: fix invalid reference to the index variable of the iterator
net/ibm/emac: wrong emac_calc_base call was used by typo
net: sched: null actions array pointer before releasing action
vhost: fix VHOST_GET_BACKEND_FEATURES ioctl request definition
r8169: add support for NCube 8168 network card
ip6_tunnel: respect ttl inherit for ip6tnl
mac80211: shorten the IBSS debug messages
mac80211: don't Tx a deauth frame if the AP forbade Tx
mac80211: Fix station bandwidth setting after channel switch
mac80211: fix a race between restart and CSA flows
...
Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides
'stack_erasing' sysctl. It can be used in runtime to control kernel
stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about
tasks via the /proc file system. In particular, /proc/<pid>/stack_depth
shows the maximum kernel stack consumption for the current and previous
syscalls. Although this information is not precise, it can be useful for
estimating the STACKLEAK performance impact for your workloads.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
The STACKLEAK feature erases the kernel stack before returning from
syscalls. That reduces the information which kernel stack leak bugs can
reveal and blocks some uninitialized stack variable attacks.
This commit introduces the STACKLEAK gcc plugin. It is needed for
tracking the lowest border of the kernel stack, which is important
for the code erasing the used part of the kernel stack at the end
of syscalls (comes in a separate commit).
The STACKLEAK feature is ported from grsecurity/PaX. More information at:
https://grsecurity.net/https://pax.grsecurity.net/
This code is modified from Brad Spengler/PaX Team's code in the last
public patch of grsecurity/PaX based on our understanding of the code.
Changes or omissions from the original code are ours and don't reflect
the original grsecurity/PaX code.
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
The STACKLEAK feature (initially developed by PaX Team) has the following
benefits:
1. Reduces the information that can be revealed through kernel stack leak
bugs. The idea of erasing the thread stack at the end of syscalls is
similar to CONFIG_PAGE_POISONING and memzero_explicit() in kernel
crypto, which all comply with FDP_RIP.2 (Full Residual Information
Protection) of the Common Criteria standard.
2. Blocks some uninitialized stack variable attacks (e.g. CVE-2017-17712,
CVE-2010-2963). That kind of bugs should be killed by improving C
compilers in future, which might take a long time.
This commit introduces the code filling the used part of the kernel
stack with a poison value before returning to userspace. Full
STACKLEAK feature also contains the gcc plugin which comes in a
separate commit.
The STACKLEAK feature is ported from grsecurity/PaX. More information at:
https://grsecurity.net/https://pax.grsecurity.net/
This code is modified from Brad Spengler/PaX Team's code in the last
public patch of grsecurity/PaX based on our understanding of the code.
Changes or omissions from the original code are ours and don't reflect
the original grsecurity/PaX code.
Performance impact:
Hardware: Intel Core i7-4770, 16 GB RAM
Test #1: building the Linux kernel on a single core
0.91% slowdown
Test #2: hackbench -s 4096 -l 2000 -g 15 -f 25 -P
4.2% slowdown
So the STACKLEAK description in Kconfig includes: "The tradeoff is the
performance impact: on a single CPU system kernel compilation sees a 1%
slowdown, other systems and workloads may vary and you are advised to
test this feature on your expected workload before deploying it".
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
A few fixes for the fallout of being a little more pedantic about
dma masks.
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Merge tag 'dma-mapping-4.19-2' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
"A few fixes for the fallout of being a little more pedantic about dma
masks"
* tag 'dma-mapping-4.19-2' of git://git.infradead.org/users/hch/dma-mapping:
of/platform: initialise AMBA default DMA masks
sparc: set a default 32-bit dma mask for OF devices
kernel/dma/direct: take DMA offset into account in dma_direct_supported
Currently we check sk_user_data is non NULL to determine if the sk
exists in a map. However, this is not sufficient to ensure the psock
or the ULP ops are not in use by another user, such as kcm or TLS. To
avoid this when adding a sock to a map also verify it is of the
correct ULP type. Additionally, when releasing a psock verify that
it is the TCP_ULP_BPF type before releasing the ULP. The error case
where we abort an update due to ULP collision can cause this error
path.
For example,
__sock_map_ctx_update_elem()
[...]
err = tcp_set_ulp_id(sock, TCP_ULP_BPF) <- collides with TLS
if (err) <- so err out here
goto out_free
[...]
out_free:
smap_release_sock() <- calling tcp_cleanup_ulp releases the
TLS ULP incorrectly.
Fixes: 2f857d0460 ("bpf: sockmap, remove STRPARSER map_flags and add multi-map support")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Pull CPU hotplug fix from Thomas Gleixner:
"Remove the stale skip_onerr member from the hotplug states"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Remove skip_onerr field from cpuhp_step structure
Pull core fixes from Thomas Gleixner:
"A small set of updates for core code:
- Prevent tracing in functions which are called from trace patching
via stop_machine() to prevent executing half patched function trace
entries.
- Remove old GCC workarounds
- Remove pointless includes of notifier.h"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Remove workaround for unreachable warnings from old GCC
notifier: Remove notifier header file wherever not used
watchdog: Mark watchdog touch functions as notrace
When a device has a DMA offset the dma capable result will change due
to the difference between the physical and DMA address. Take that into
account.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
When notifiers were there, `skip_onerr` was used to avoid calling
particular step startup/teardown callbacks in the CPU up/down rollback
path, which made the hotplug asymmetric.
As notifiers are gone now after the full state machine conversion, the
`skip_onerr` field is no longer required.
Remove it from the structure and its usage.
Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1535439294-31426-1-git-send-email-mojha@codeaurora.org
Allocating a list_head structure that is almost never used, and, when
used, is used only during early boot (rcu_init() and earlier), is a bit
wasteful. This commit therefore eliminates that list_head in favor of
the one in the work_struct structure. This is safe because the work_struct
structure cannot be used until after rcu_init() returns.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Event tracing is moving to SRCU in order to take advantage of the fact
that SRCU may be safely used from idle and even offline CPUs. However,
event tracing can invoke call_srcu() very early in the boot process,
even before workqueue_init_early() is invoked (let alone rcu_init()).
Therefore, call_srcu()'s attempts to queue work fail miserably.
This commit therefore detects this situation, and refrains from attempting
to queue work before rcu_init() time, but does everything else that it
would have done, and in addition, adds the srcu_struct to a global list.
The rcu_init() function now invokes a new srcu_init() function, which
is empty if CONFIG_SRCU=n. Otherwise, srcu_init() queues work for
each srcu_struct on the list. This all happens early enough in boot
that there is but a single CPU with interrupts disabled, which allows
synchronization to be dispensed with.
Of course, the queued work won't actually be invoked until after
workqueue_init() is invoked, which happens shortly after the scheduler
is up and running. This means that although call_srcu() may be invoked
any time after per-CPU variables have been set up, there is still a very
narrow window when synchronize_srcu() won't work, and this window
extends from the time that the scheduler starts until the time that
workqueue_init() returns. This can be fixed in a manner similar to
the fix for synchronize_rcu_expedited() and friends, but until someone
actually needs to use synchronize_srcu() during this window, this fix
is added churn for no benefit.
Finally, note that Tree SRCU's new srcu_init() function invokes
queue_work() rather than the queue_delayed_work() function that is
invoked post-boot. The reason is that queue_delayed_work() will (as you
would expect) post a timer, and timers have not yet been initialized.
So use of queue_work() avoids the complaints about use of uninitialized
spinlocks that would otherwise result. Besides, some delay is already
provide by the aforementioned fact that the queued work won't actually
be invoked until after the scheduler is up and running.
Requested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
1e64b15a4b ("rcu: Fix grace-period hangs due to race with CPU offline")
added spinlock_t ofl_lock to the rcu_state structure, then takes it with
preemption disabled during CPU offline, which gives the -rt patchset's
sleeping spinlock heartburn.
This commit therefore converts ->ofl_lock to raw_spinlock_t.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
The rcu_data structure's ->dynticks_fqs is incremented but never
accesses. Its ->cond_resched_completed field isn't used at all.
This commit therefore removes both fields.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit move ->dynticks from the rcu_dynticks structure to the
rcu_data structure, replacing the field of the same name. It also updates
the code to access ->dynticks from the rcu_data structure and to use the
rcu_data structure rather than following to now-gone ->dynticks field
to the now-gone rcu_dynticks structure. While in the area, this commit
also fixes up comments.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes ->dynticks_nesting and ->dynticks_nmi_nesting from
the rcu_dynticks structure and updates the code to access them from the
rcu_data structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes ->rcu_need_heavy_qs and ->rcu_urgent_qs from the
rcu_dynticks structure and updates the code to access them from the
rcu_data structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes ->all_lazy, ->nonlazy_posted and ->nonlazy_posted_snap
from the rcu_dynticks structure and updates the code to access them from
the rcu_data structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes ->last_accelerate and ->last_advance_all from the
rcu_dynticks structure and updates the code to access them from the
rcu_data structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes ->tick_nohz_enabled_snap from the rcu_dynticks
structure and updates the code to access it from the rcu_data
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only ever one rcu_data structure per CPU, there is no
need for a separate rcu_dynticks structure. This commit therefore adds
the rcu_dynticks fields into the rcu_data structure in preparation for
removing the rcu_dynticks structure entirely. Note that the ->dynticks
field will be handled specially because there is a field by that name
in both structures.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The resched_cpu() interface is quite handy, but it does acquire the
specified CPU's runqueue lock, which does not come for free. This
commit therefore substitutes the following when directing resched_cpu()
at the current CPU:
set_tsk_need_resched(current);
set_preempt_need_resched();
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Because nohz_full CPUs can leave the scheduler-clock interrupt disabled
even when in kernel mode, RCU cannot rely on rcu_check_callbacks() to
enlist the scheduler's aid in extracting a quiescent state from such CPUs.
This commit therefore more aggressively uses resched_cpu() on nohz_full
CPUs that fail to pass through a quiescent state in a timely manner.
By default, the resched_cpu() beating starts 300 milliseconds into the
quiescent state.
While in the neighborhood, add a ->last_fqs_resched field to the rcu_data
structure in order to rate-limit resched_cpu() calls from the RCU
grace-period kthread.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The jiffies_till_sched_qs value used to determine how old a grace period
must be before RCU enlists the help of the scheduler to force a quiescent
state on the holdout CPU. Currently, this defaults to HZ/10 regardless of
system size and may be set only at boot time. This can be a problem for
very large systems, because if the values of the jiffies_till_first_fqs
and jiffies_till_next_fqs kernel parameters are left at their defaults,
they are calculated to increase as the number of CPUs actually configured
on the system increases. Thus, on a sufficiently large system, RCU would
enlist the help of the scheduler before the grace-period kthread had a
chance to scan for idle CPUs, which wastes CPU time.
This commit therefore allows jiffies_till_sched_qs to be set, if desired,
but if left as default, computes is as jiffies_till_first_fqs plus twice
jiffies_till_next_fqs, thus allowing three force-quiescent-state scans
for idle CPUs. This scales with the number of CPUs, providing sensible
default values.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds rcu_head_init() and rcu_head_after_call_rcu() functions
to help RCU users detect when another CPU has passed the specified
rcu_head structure and function to call_rcu(). The rcu_head_init()
should be invoked before making the structure visible to RCU readers,
and then the rcu_head_after_call_rcu() may be invoked from within
an RCU read-side critical section on an rcu_head structure that
was obtained during a traversal of the data structure in question.
The rcu_head_after_call_rcu() function will return true if the rcu_head
structure has already been passed (with the specified function) to
call_rcu(), otherwise it will return false.
If rcu_head_init() has not been invoked on the rcu_head structure
or if the rcu_head (AKA callback) has already been invoked, then
rcu_head_after_call_rcu() will do WARN_ON_ONCE().
Reported-by: NeilBrown <neilb@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Apply neilb naming feedback. ]
The ->rcu_qs_ctr counter was intended to allow providing a lightweight
report of a quiescent state to all RCU flavors. But now that there is
only one flavor of RCU in any one running kernel, there is no point in
having this feature. This commit therefore removes the ->rcu_qs_ctr
field from the rcu_dynticks structure and the ->rcu_qs_ctr_snap field
from the rcu_data structure. This results in the "rqc" option to the
rcu_fqs trace event no longer being used, so this commit also removes the
"rqc" description from the header comment.
While in the neighborhood, this commit also causes the forward-progress
request .rcu_need_heavy_qs be set one jiffies_till_sched_qs interval
later in the grace period than the first setting of .rcu_urgent_qs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
If a long-running CPU-bound in-kernel task invokes call_rcu(), the
callback won't be invoked until the next context switch. If there are
no other runnable tasks (which is not an uncommon situation on deep
embedded systems), the callback might never be invoked.
This commit therefore causes rcu_check_callbacks() to ask the scheduler
for a context switch if there are callbacks posted that are still waiting
for a grace period.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that RCU can have readers with multiple segments, it is quite
possible that a specific sequence of reader segments might result in
an rcutorture failure (reader spans a full grace period as detected
by one of the grace-period primitives) or an rcutorture close call
(reader potentially spans a full grace period based on reading out
the RCU implementation's grace-period counter, but with no ordering).
In such cases, it would clearly ease debugging if the offending specific
sequence was known. For the first reader encountering a failure or a
close call, this commit therefore dumps out the segments, delay durations,
and whether or not the reader was preempted.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Mark variables static, as suggested by kbuild test robot. ]
The patch making need_resched() respond to urgent RCU-QS needs used
is_idle_task(current) to detect an interrupt from idle, which does work
reasonably, but is (in theory at least) vulnerable to loops containing
need_resched() invoked from within RCU_NONIDLE() or its tracepoint
equivalent. This commit therefore moves rcu_is_cpu_rrupt_from_idle()
to a place from which rcu_check_callbacks() can invoke it and replaces
the is_idle_task(current) with rcu_is_cpu_rrupt_from_idle().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The per-CPU rcu_dynticks.rcu_urgent_qs variable communicates an urgent
need for an RCU quiescent state from the force-quiescent-state processing
within the grace-period kthread to context switches and to cond_resched().
Unfortunately, such urgent needs are not communicated to need_resched(),
which is sometimes used to decide when to invoke cond_resched(), for
but one example, within the KVM vcpu_run() function. As of v4.15, this
can result in synchronize_sched() being delayed by up to ten seconds,
which can be problematic, to say nothing of annoying.
This commit therefore checks rcu_dynticks.rcu_urgent_qs from within
rcu_check_callbacks(), which is invoked from the scheduling-clock
interrupt handler. If the current task is not an idle task and is
not executing in usermode, a context switch is forced, and either way,
the rcu_dynticks.rcu_urgent_qs variable is set to false. If the current
task is an idle task, then RCU's dyntick-idle code will detect the
quiescent state, so no further action is required. Similarly, if the
task is executing in usermode, other code in rcu_check_callbacks() and
its called functions will report the corresponding quiescent state.
Reported-by: Marius Hillenbrand <mhillenb@amazon.de>
Reported-by: David Woodhouse <dwmw2@infradead.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because rcu_barrier() is a one-line wrapper function for _rcu_barrier()
and because nothing else calls _rcu_barrier(), this commit inlines
_rcu_barrier() into rcu_barrier().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that rcu_all_qs() is used only in !PREEMPT builds, move it to
tree_plugin.h so that it is defined only in those builds. This in
turn means that rcu_momentary_dyntick_idle() is only used in !PREEMPT
builds, but it is simply marked __maybe_unused in order to keep it
near the rest of the dyntick-idle code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes rcu_sched_get_gp_seq(), rcu_bh_get_gp_seq(),
rcu_exp_batches_completed_sched(), rcu_sched_force_quiescent_state(),
and rcu_bh_force_quiescent_state(), which are no longer used because
rcutorture no longer does "rcu_bh" and "rcu_sched" torture types.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that the RCU-bh and RCU-sched update-side functions are simple
wrappers around their RCU counterparts, there isn't a whole lot of point
in testing them. This commit therefore removes the "rcu_bh" and "sched"
torture types from rcuperf.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that the RCU-bh and RCU-sched update-side functions are simple
wrappers around their RCU counterparts, there isn't a whole lot of point
in testing them. This commit therefore removes the "rcu_bh" and "sched"
torture types from rcutorture.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that the RCU-bh and RCU-sched update-side functions are simple
wrappers around their RCU counterparts, there isn't a whole lot of
point in testing them. This commit therefore removes the self-test
capability and removes the corresponding kernel-boot parameters.
It also updates the various rcutorture .boot files to remove the
kernel boot parameters that call for testing RCU-bh and RCU-sched.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Since there is now a single consolidated RCU flavor, rcutorture
needs to test extending of RCU readers via rcu_read_lock_bh() and
rcu_read_lock_sched(). This commit adds this support, with added checks
(just like for local_bh_enable()) to ensure that rcu_read_unlock_bh()
will not be invoked while interrupts are disabled.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit saves a few lines by consolidating the RCU-sched function
definitions at the end of include/linux/rcupdate.h. This consolidation
also makes it easier to remove them all when the time comes.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit saves a few lines by consolidating the RCU-bh function
definitions at the end of include/linux/rcupdate.h. This consolidation
also makes it easier to remove them all when the time comes.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_gp_kthread() function is long and deeply indented, so this
commit pulls the loop that repeatedly invokes rcu_gp_fqs() into a new
rcu_gp_fqs_loop() function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Consolidation of the RCU flavors into one makes increment_cpu_stall_ticks()
a trivial one-line function with only one caller. This commit therefore
inlines it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Pointers to rcu_data structures should be named rdp, not rsp. This
commit therefore makes this change.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point in
maintaining a pointer to it. This commit therefore replaces rsp with
&rcu_state in rcu_cpu_starting() and rcu_init_one().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point
in maintaining a pointer to it. This commit therefore replaces rsp
with &rcu_state in rcu_barrier_callback(), rcu_barrier_func(), and
_rcu_barrier().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point in
maintaining a pointer to it. This commit therefore replaces rsp with
&rcu_state in rcu_report_qs_rnp(), force_quiescent_state(), and
rcu_check_gp_start_stall().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point in
maintaining a pointer to it. This commit therefore replaces rsp with
&rcu_state in rcu_do_batch(), invoke_rcu_callbacks(), and __call_rcu().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point
in maintaining a pointer to it. This commit therefore replaces
rsp with &rcu_state in rcu_start_this_gp(), rcu_accelerate_cbs(),
__note_gp_changes(), rcu_gp_init(), rcu_gp_fqs(), rcu_gp_cleanup(),
rcu_gp_kthread(), and rcu_report_qs_rsp().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is less point
in maintaining a pointer to it. This commit therefore replaces rsp
with &rcu_state in print_other_cpu_stall(), print_cpu_stall(), and
check_cpu_stall().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes the rsp and gpa local variables, repurposes the j
local variable and adds a gpk (GP kthread) local to improve readability.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit restructures rcutorture_get_gp_data() to take advantage of
the fact that there is only one flavor of RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only ever a single flavor of RCU in a given kernel
build, there isn't a whole lot of point in having a flavor-traversal
macro. This commit therefore removes it and converts calls to it to
straightline code, inlining trivial functions as appropriate.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes the last non-flavor-traversal rsp local variable from
kernel/rcu/tree_plugin.h in favor of &rcu_state. The flavor-traversal
locals will be removed with the removal of flavor traversal.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that there is only one rcu_state structure, there is no need for the
rcu_data structure to indicate which it corresponds to. This commit
therefore removes the rcu_data structure's ->rsp field, replacing all
remaining uses of it with &rcu_state.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the Linux
kernel, so there is no need to pass it as a parameter to RCU's rcu_node
tree's accessor macros. This commit therefore removes the rsp parameter
from those macros in kernel/rcu/rcu.h, and removes some now-unused rsp
local variables while in the area.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to
RCU's functions. This commit therefore removes the rsp parameter
from the code in kernel/rcu/tree_exp.h, and removes all of the
rsp local variables while in the area.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to
RCU's functions. This commit therefore removes the rsp parameter
from rcu_nocb_cpu_needs_barrier(), rcu_spawn_one_nocb_kthread(),
rcu_organize_nocb_kthreads(), rcu_nocb_cpu_needs_barrier(), and
rcu_nohz_full_cpu().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions. This commit therefore removes the rsp parameter from
print_cpu_stall_info().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions. This commit therefore removes the rsp parameter from
rcu_spawn_one_boost_kthread().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions. This commit therefore removes the rsp parameter from
dump_blkd_tasks() and rcu_preempt_blocked_readers_cgp().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions. This commit therefore removes the rsp parameter from
rcu_print_detail_task_stall().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions. This commit therefore removes the rsp parameter from
rcu_init_one() and rcu_dump_rcu_node_tree().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There now is only one rcu_state structure in a given build of
the Linux kernel, so there is no need to pass it as a parameter
to RCU's functions. This commit therefore removes the rsp
parameter from rcu_boot_init_percpu_data(), rcu_init_percpu_data(),
rcu_cleanup_dying_idle_cpu(), and rcu_migrate_callbacks(). While in
the neighborhood, line the last three into rcutree_prepare_cpu(),
rcu_report_dead() and rcutree_migrate_callbacks(), respectively.
This also gets rid of the for_each_rcu_flavor() calls that were in
those tree functions.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Alexander Duyck