Vince reported that commit 15a2d4de0e ("perf: Always destroy groups
on exit") causes a regression with grouped events. In particular his
read_group_attached.c test fails.
https://github.com/deater/perf_event_tests/blob/master/tests/bugs/read_group_attached.c
Because of the context switch optimization in
perf_event_context_sched_out() the 'original' event may end up in the
child process and when that exits the change in the patch in question
destroys the actual grouping.
Therefore revert that change and only destroy inherited groups.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-zedy3uktcp753q8fw8dagx7a@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
running:
# perf probe -x /lib/libc.so.6 syscall
# echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable
# perf record -e probe_libc:syscall whatever
kills the uprobe. Along the way he found some other minor bugs and clean ups
that he fixed up making it a total of 4 patches.
Doing unrelated work, I found that the reading of the ftrace trace
file disables all function tracer callbacks. This was fine when ftrace
was the only user, but now that it's used by perf and kprobes, this
is a bug where reading trace can disable kprobes and perf. A very unexpected
side effect and should be fixed.
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Merge tag 'trace-fixes-v3.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Oleg Nesterov found and fixed a bug in the perf/ftrace/uprobes code
where running:
# perf probe -x /lib/libc.so.6 syscall
# echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable
# perf record -e probe_libc:syscall whatever
kills the uprobe. Along the way he found some other minor bugs and
clean ups that he fixed up making it a total of 4 patches.
Doing unrelated work, I found that the reading of the ftrace trace
file disables all function tracer callbacks. This was fine when
ftrace was the only user, but now that it's used by perf and kprobes,
this is a bug where reading trace can disable kprobes and perf. A
very unexpected side effect and should be fixed"
* tag 'trace-fixes-v3.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Remove ftrace_stop/start() from reading the trace file
tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()
tracing/uprobes: Kill the bogus UPROBE_HANDLER_REMOVE code in uprobe_dispatcher()
uprobes: Change unregister/apply to WARN() if uprobe/consumer is gone
tracing/uprobes: Revert "Support mix of ftrace and perf"
The context check in perf_event_context_sched_out allows
non-cloned context to be part of the optimized schedule
out switch.
This could move non-cloned context into another workload
child. Once this child exits, the context is closed and
leaves all original (parent) events in closed state.
Any other new cloned event will have closed state and not
measure anything. And probably causing other odd bugs.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1403598026-2310-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add WARN_ON's into uprobe_unregister() and uprobe_apply() to ensure
that nobody tries to play with the dead uprobe/consumer. This helps
to catch the bugs like the one fixed by the previous patch.
In the longer term we should fix this poorly designed interface.
uprobe_register() should return "struct uprobe *" which should be
passed to apply/unregister. Plus other semantic changes, see the
changelog in commit 41ccba029e.
Link: http://lkml.kernel.org/p/20140627170140.GA18322@redhat.com
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull more perf updates from Ingo Molnar:
"A second round of perf updates:
- wide reaching kprobes sanitization and robustization, with the hope
of fixing all 'probe this function crashes the kernel' bugs, by
Masami Hiramatsu.
- uprobes updates from Oleg Nesterov: tmpfs support, corner case
fixes and robustization work.
- perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
et al:
* Add support to accumulate hist periods (Namhyung Kim)
* various fixes, refactorings and enhancements"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
perf: Differentiate exec() and non-exec() comm events
perf: Fix perf_event_comm() vs. exec() assumption
uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
perf/documentation: Add description for conditional branch filter
perf/x86: Add conditional branch filtering support
perf/tool: Add conditional branch filter 'cond' to perf record
perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
uprobes: Teach copy_insn() to support tmpfs
uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
perf/x86: Use common PMU interrupt disabled code
perf/ARM: Use common PMU interrupt disabled code
perf: Disable sampled events if no PMU interrupt
perf: Fix use after free in perf_remove_from_context()
perf tools: Fix 'make help' message error
perf record: Fix poll return value propagation
perf tools: Move elide bool into perf_hpp_fmt struct
perf tools: Remove elide setup for SORT_MODE__MEMORY mode
perf tools: Fix "==" into "=" in ui_browser__warning assignment
perf tools: Allow overriding sysfs and proc finding with env var
perf tools: Consider header files outside perf directory in tags target
...
Pull cgroup updates from Tejun Heo:
"A lot of activities on cgroup side. Heavy restructuring including
locking simplification took place to improve the code base and enable
implementation of the unified hierarchy, which currently exists behind
a __DEVEL__ mount option. The core support is mostly complete but
individual controllers need further work. To explain the design and
rationales of the the unified hierarchy
Documentation/cgroups/unified-hierarchy.txt
is added.
Another notable change is css (cgroup_subsys_state - what each
controller uses to identify and interact with a cgroup) iteration
update. This is part of continuing updates on css object lifetime and
visibility. cgroup started with reference count draining on removal
way back and is now reaching a point where csses behave and are
iterated like normal refcnted objects albeit with some complexities to
allow distinguishing the state where they're being deleted. The css
iteration update isn't taken advantage of yet but is planned to be
used to simplify memcg significantly"
* 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits)
cgroup: disallow disabled controllers on the default hierarchy
cgroup: don't destroy the default root
cgroup: disallow debug controller on the default hierarchy
cgroup: clean up MAINTAINERS entries
cgroup: implement css_tryget()
device_cgroup: use css_has_online_children() instead of has_children()
cgroup: convert cgroup_has_live_children() into css_has_online_children()
cgroup: use CSS_ONLINE instead of CGRP_DEAD
cgroup: iterate cgroup_subsys_states directly
cgroup: introduce CSS_RELEASED and reduce css iteration fallback window
cgroup: move cgroup->serial_nr into cgroup_subsys_state
cgroup: link all cgroup_subsys_states in their sibling lists
cgroup: move cgroup->sibling and ->children into cgroup_subsys_state
cgroup: remove cgroup->parent
device_cgroup: remove direct access to cgroup->children
memcg: update memcg_has_children() to use css_next_child()
memcg: remove tasks/children test from mem_cgroup_force_empty()
cgroup: remove css_parent()
cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css
cgroup: use cgroup->self.refcnt for cgroup refcnting
...
This reverts commit 3090ffb5a2.
Re-enable the mmap2 interface as we will have a user soon.
Since things have changed since perf disabled mmap2, small tweaks
to the revert had to be done:
o commit 9d4ecc88 forced (n!=8) to become (n<7)
o a new libunwind test needed updating to use mmap2 interface
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1401461382-209586-1-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
The mmap2 interface was missing the protection and flags bits needed to
accurately determine if a mmap memory area was shared or private and
if it was readable or not.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
[tweaked patch to compile and wrote changelog]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1400526833-141779-2-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
perf tools like 'perf report' can aggregate samples by comm strings,
which generally works. However, there are other potential use-cases.
For example, to pair up 'calls' with 'returns' accurately (from branch
events like Intel BTS) it is necessary to identify whether the process
has exec'd. Although a comm event is generated when an 'exec' happens
it is also generated whenever the comm string is changed on a whim
(e.g. by prctl PR_SET_NAME). This patch adds a flag to the comm event
to differentiate one case from the other.
In order to determine whether the kernel supports the new flag, a
selection bit named 'exec' is added to struct perf_event_attr. The
bit does nothing but will cause perf_event_open() to fail if the bit
is set on kernels that do not have it defined.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/537D9EBE.7030806@intel.com
Cc: Paul Mackerras <paulus@samba.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_event_comm() assumes that set_task_comm() is only called on
exec(), and in particular that its only called on current.
Neither are true, as Dave reported a WARN triggered by set_task_comm()
being called on !current.
Separate the exec() hook from the comm hook.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20140521153219.GH5226@laptop.programming.kicks-ass.net
[ Build fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull ARM updates from Russell King:
- Major clean-up of the L2 cache support code. The existing mess was
becoming rather unmaintainable through all the additions that others
have done over time. This turns it into a much nicer structure, and
implements a few performance improvements as well.
- Clean up some of the CP15 control register tweaks for alignment
support, moving some code and data into alignment.c
- DMA properties for ARM, from Santosh and reviewed by DT people. This
adds DT properties to specify bus translations we can't discover
automatically, and to indicate whether devices are coherent.
- Hibernation support for ARM
- Make ftrace work with read-only text in modules
- add suspend support for PJ4B CPUs
- rework interrupt masking for undefined instruction handling, which
allows us to enable interrupts earlier in the handling of these
exceptions.
- support for big endian page tables
- fix stacktrace support to exclude stacktrace functions from the
trace, and add save_stack_trace_regs() implementation so that kprobes
can record stack traces.
- Add support for the Cortex-A17 CPU.
- Remove last vestiges of ARM710 support.
- Removal of ARM "meminfo" structure, finally converting us solely to
memblock to handle the early memory initialisation.
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (142 commits)
ARM: ensure C page table setup code follows assembly code (part II)
ARM: ensure C page table setup code follows assembly code
ARM: consolidate last remaining open-coded alignment trap enable
ARM: remove global cr_no_alignment
ARM: remove CPU_CP15 conditional from alignment.c
ARM: remove unused adjust_cr() function
ARM: move "noalign" command line option to alignment.c
ARM: provide common method to clear bits in CPU control register
ARM: 8025/1: Get rid of meminfo
ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type
ARM: 8066/1: correction for ARM patch 8031/2
ARM: 8049/1: ftrace/add save_stack_trace_regs() implementation
ARM: 8065/1: remove last use of CONFIG_CPU_ARM710
ARM: 8062/1: Modify ldrt fixup handler to re-execute the userspace instruction
ARM: 8047/1: rwsem: use asm-generic rwsem implementation
ARM: l2c: trial at enabling some Cortex-A9 optimisations
ARM: l2c: add warnings for stuff modifying aux_ctrl register values
ARM: l2c: print a warning with L2C-310 caches if the cache size is modified
ARM: l2c: remove old .set_debug method
ARM: l2c: kill L2X0_AUX_CTRL_MASK before anyone else makes use of this
...
tmpfs is widely used but as Denys reports shmem_aops doesn't have
->readpage() and thus you can't probe a binary on this filesystem.
As Hugh suggested we can use shmem_read_mapping_page() in this case,
just we need to check shmem_mapping() if ->readpage == NULL.
Reported-by: Denys Vlasenko <dvlasenk@redhat.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140519184136.GB6750@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
copy_insn() fails with -EIO if ->readpage == NULL, but this error
is not propagated unless uprobe_register() path finds ->mm which
already mmaps this file. In this case (say) "perf record" does not
actually install the probe, but the user can't know about this.
Move this check into uprobe_register() so that this problem can be
detected earlier and reported to user.
Note: this is still not perfect,
- copy_insn() and arch_uprobe_analyze_insn() should be called
by uprobe_register() but this is not simple, we need vm_file
for read_mapping_page() (although perhaps we can pass NULL),
and we need ->mm for is_64bit_mm() (although this logic is
broken anyway).
- uprobe_register() should be called by create_trace_uprobe(),
not by probe_event_enable(), so that an error can be detected
at "perf probe -x" time. This also needs more changes in the
core uprobe code, uprobe register/unregister interface was
poorly designed from the very beginning.
Reported-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140519184054.GA6750@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add common code to generate -ENOTSUPP at event creation time if an
architecture attempts to create a sampled event and
PERF_PMU_NO_INTERRUPT is set.
This adds a new pmu->capabilities flag. Initially we only support
PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating
hardware interrupts) but there are other capabilities that can be
added later.
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Will Deacon <will.deacon@arm.com>
[peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While that mutex should guard the elements, it doesn't guard against the
use-after-free that's from list_for_each_entry_rcu().
__perf_event_exit_task() can actually free the event.
And because list addition/deletion is guarded by both ctx->mutex and
ctx->lock, holding ctx->mutex is sufficient for reading the list, so we
don't actually need the rcu list iteration.
Fixes: 3a497f4863 ("perf: Simplify perf_event_exit_task_context()")
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Jones <davej@redhat.com>
Cc: acme@ghostprotocols.net
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140529170024.GA2315@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf updates from Ingo Molnar:
"The tooling changes maintained by Jiri Olsa until Arnaldo is on
vacation:
User visible changes:
- Add -F option for specifying output fields (Namhyung Kim)
- Propagate exit status of a command line workload for record command
(Namhyung Kim)
- Use tid for finding thread (Namhyung Kim)
- Clarify the output of perf sched map plus small sched command
fixes (Dongsheng Yang)
- Wire up perf_regs and unwind support for ARM64 (Jean Pihet)
- Factor hists statistics counts processing which in turn also fixes
several bugs in TUI report command (Namhyung Kim)
- Add --percentage option to control absolute/relative percentage
output (Namhyung Kim)
- Add --list-cmds to 'kmem', 'mem', 'lock' and 'sched', for use by
completion scripts (Ramkumar Ramachandra)
Development/infrastructure changes and fixes:
- Android related fixes for pager and map dso resolving (Michael
Lentine)
- Add libdw DWARF post unwind support for ARM (Jean Pihet)
- Consolidate types.h for ARM and ARM64 (Jean Pihet)
- Fix possible null pointer dereference in session.c (Masanari Iida)
- Cleanup, remove unused variables in map_switch_event() (Dongsheng
Yang)
- Remove nr_state_machine_bugs in perf latency (Dongsheng Yang)
- Remove usage of trace_sched_wakeup(.success) (Peter Zijlstra)
- Cleanups for perf.h header (Jiri Olsa)
- Consolidate types.h and export.h within tools (Borislav Petkov)
- Move u64_swap union to its single user's header, evsel.h (Borislav
Petkov)
- Fix for s390 to properly parse tracepoints plus test code
(Alexander Yarygin)
- Handle EINTR error for readn/writen (Namhyung Kim)
- Add a test case for hists filtering (Namhyung Kim)
- Share map_groups among threads of the same group (Arnaldo Carvalho
de Melo, Jiri Olsa)
- Making some code (cpu node map and report parse callchain callback)
global to be usable by upcomming changes (Don Zickus)
- Fix pmu object compilation error (Jiri Olsa)
Kernel side changes:
- intrusive uprobes fixes from Oleg Nesterov. Since the interface is
admin-only, and the bug only affects user-space ("any probed
jmp/call can kill the application"), we queued these fixes via the
development tree, as a special exception.
- more fuzzer motivated race fixes and related refactoring and
robustization.
- allow PMU drivers to be built as modules. (No actual module yet,
because the x86 Intel uncore module wasn't ready in time for this)"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
perf tools: Add automatic remapping of Android libraries
perf tools: Add cat as fallback pager
perf tests: Add a testcase for histogram output sorting
perf tests: Factor out print_hists_*()
perf tools: Introduce reset_output_field()
perf tools: Get rid of obsolete hist_entry__sort_list
perf hists: Reset width of output fields with header length
perf tools: Skip elided sort entries
perf top: Add --fields option to specify output fields
perf report/tui: Fix a bug when --fields/sort is given
perf tools: Add ->sort() member to struct sort_entry
perf report: Add -F option to specify output fields
perf tools: Call perf_hpp__init() before setting up GUI browsers
perf tools: Consolidate management of default sort orders
perf tools: Allow hpp fields to be sort keys
perf ui: Get rid of callback from __hpp__fmt()
perf tools: Consolidate output field handling to hpp format routines
perf tools: Use hpp formats to sort final output
perf tools: Support event grouping in hpp ->sort()
perf tools: Use hpp formats to sort hist entries
...
After instruction write into xol area, on ARM V7
architecture code need to flush dcache and icache to sync
them up for given set of addresses. Having just
'flush_dcache_page(page)' call is not enough - it is
possible to have stale instruction sitting in icache
for given xol area slot address.
Introduce arch_uprobe_ixol_copy weak function
that by default calls uprobes copy_to_page function and
than flush_dcache_page function and on ARM define new one
that handles xol slot copy in ARM specific way
flush_uprobe_xol_access function shares/reuses implementation
with/of flush_ptrace_access function and takes care of writing
instruction to user land address space on given variety of
different cache types on ARM CPUs. Because
flush_uprobe_xol_access does not have vma around
flush_ptrace_access was split into two parts. First that
retrieves set of condition from vma and common that receives
those conditions as flags.
Note ARM cache flush function need kernel address
through which instruction write happened, so instead
of using uprobes copy_to_page function changed
code to explicitly map page and do memcpy.
Note arch_uprobe_copy_ixol function, in similar way as
copy_to_user_page function, has preempt_disable/preempt_enable.
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Alexander noticed that we use RCU iteration on rb->event_list but do
not use list_{add,del}_rcu() to add,remove entries to that list, nor
do we observe proper grace periods when re-using the entries.
Merge ring_buffer_detach() into ring_buffer_attach() such that
attaching to the NULL buffer is detaching.
Furthermore, ensure that between any 'detach' and 'attach' of the same
event we observe the required grace period, but only when strictly
required. In effect this means that only ioctl(.request =
PERF_EVENT_IOC_SET_OUTPUT) will wait for a grace period, while the
normal initial attach and final detach will not be delayed.
This patch should, I think, do the right thing under all
circumstances, the 'normal' cases all should never see the extra grace
period, but the two cases:
1) PERF_EVENT_IOC_SET_OUTPUT on an event which already has a
ring_buffer set, will now observe the required grace period between
removing itself from the old and attaching itself to the new buffer.
This case is 'simple' in that both buffers are present in
perf_event_set_output() one could think an unconditional
synchronize_rcu() would be sufficient; however...
2) an event that has a buffer attached, the buffer is destroyed
(munmap) and then the event is attached to a new/different buffer
using PERF_EVENT_IOC_SET_OUTPUT.
This case is more complex because the buffer destruction does:
ring_buffer_attach(.rb = NULL)
followed by the ioctl() doing:
ring_buffer_attach(.rb = foo);
and we still need to observe the grace period between these two
calls due to us reusing the event->rb_entry list_head.
In order to make 2 happen we use Paul's latest cond_synchronize_rcu()
call.
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507123526.GD13658@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The perf cpu offline callback takes down all cpu context
events and releases swhash->swevent_hlist.
This could race with task context software event being just
scheduled on this cpu via perf_swevent_add while cpu hotplug
code already cleaned up event's data.
The race happens in the gap between the cpu notifier code
and the cpu being actually taken down. Note that only cpu
ctx events are terminated in the perf cpu hotplug code.
It's easily reproduced with:
$ perf record -e faults perf bench sched pipe
while putting one of the cpus offline:
# echo 0 > /sys/devices/system/cpu/cpu1/online
Console emits following warning:
WARNING: CPU: 1 PID: 2845 at kernel/events/core.c:5672 perf_swevent_add+0x18d/0x1a0()
Modules linked in:
CPU: 1 PID: 2845 Comm: sched-pipe Tainted: G W 3.14.0+ #256
Hardware name: Intel Corporation Montevina platform/To be filled by O.E.M., BIOS AMVACRB1.86C.0066.B00.0805070703 05/07/2008
0000000000000009 ffff880077233ab8 ffffffff81665a23 0000000000200005
0000000000000000 ffff880077233af8 ffffffff8104732c 0000000000000046
ffff88007467c800 0000000000000002 ffff88007a9cf2a0 0000000000000001
Call Trace:
[<ffffffff81665a23>] dump_stack+0x4f/0x7c
[<ffffffff8104732c>] warn_slowpath_common+0x8c/0xc0
[<ffffffff8104737a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8110fb3d>] perf_swevent_add+0x18d/0x1a0
[<ffffffff811162ae>] event_sched_in.isra.75+0x9e/0x1f0
[<ffffffff8111646a>] group_sched_in+0x6a/0x1f0
[<ffffffff81083dd5>] ? sched_clock_local+0x25/0xa0
[<ffffffff811167e6>] ctx_sched_in+0x1f6/0x450
[<ffffffff8111757b>] perf_event_sched_in+0x6b/0xa0
[<ffffffff81117a4b>] perf_event_context_sched_in+0x7b/0xc0
[<ffffffff81117ece>] __perf_event_task_sched_in+0x43e/0x460
[<ffffffff81096f1e>] ? put_lock_stats.isra.18+0xe/0x30
[<ffffffff8107b3c8>] finish_task_switch+0xb8/0x100
[<ffffffff8166a7de>] __schedule+0x30e/0xad0
[<ffffffff81172dd2>] ? pipe_read+0x3e2/0x560
[<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70
[<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70
[<ffffffff8166b464>] preempt_schedule_irq+0x44/0x70
[<ffffffff816707f0>] retint_kernel+0x20/0x30
[<ffffffff8109e60a>] ? lockdep_sys_exit+0x1a/0x90
[<ffffffff812a4234>] lockdep_sys_exit_thunk+0x35/0x67
[<ffffffff81679321>] ? sysret_check+0x5/0x56
Fixing this by tracking the cpu hotplug state and displaying
the WARN only if current cpu is initialized properly.
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: stable@vger.kernel.org
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1396861448-10097-1-git-send-email-jolsa@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Vince reported that using a large sample_period (one with bit 63 set)
results in wreckage since while the sample_period is fundamentally
unsigned (negative periods don't make sense) the way we implement
things very much rely on signed logic.
So limit sample_period to 63 bits to avoid tripping over this.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the probed insn triggers a trap, ->si_addr = regs->ip is technically
correct, but this is not what the signal handler wants; we need to pass
the address of the probed insn, not the address of xol slot.
Add the new arch-agnostic helper, uprobe_get_trap_addr(), and change
fill_trap_info() and math_error() to use it. !CONFIG_UPROBES case in
uprobes.h uses a macro to avoid include hell and ensure that it can be
compiled even if an architecture doesn't define instruction_pointer().
Test-case:
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
extern void probe_div(void);
void sigh(int sig, siginfo_t *info, void *c)
{
int passed = (info->si_addr == probe_div);
printf(passed ? "PASS\n" : "FAIL\n");
_exit(!passed);
}
int main(void)
{
struct sigaction sa = {
.sa_sigaction = sigh,
.sa_flags = SA_SIGINFO,
};
sigaction(SIGFPE, &sa, NULL);
asm (
"xor %ecx,%ecx\n"
".globl probe_div; probe_div:\n"
"idiv %ecx\n"
);
return 0;
}
it fails if probe_div() is probed.
Note: show_unhandled_signals users should probably use this helper too,
but we need to cleanup them first.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Hugh says:
The one I noticed was that it forgets all about memcg (because
it was copied from KSM, and there the replacement page has already
been charged to a memcg). See how mm/memory.c do_anonymous_page()
does a mem_cgroup_charge_anon().
Hopefully not a big problem, uprobes is a system-wide thing and only
root can insert the probes. But I agree, should be fixed anyway.
Add mem_cgroup_{un,}charge_anon() into uprobe_write_opcode(). To simplify
the error handling (and avoid the new "uncharge" label) the patch also
moves anon_vma_prepare() up before we alloc/charge the new page.
While at it fix the comment about ->mmap_sem, it is held for write.
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero. cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero. Let's rename the existing trygets so that they clearly
indicate that they're onliness.
I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.
Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir(). This is pure rename.
v2: cgroup_freezer grew new usages of css_tryget(). Update
accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Instead of jumping through hoops to make sure to find (and exit) each
event, do it the simple straight fwd way.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-tij931199thfkys8vbnokdpf@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Primarily make perf_event_release_kernel() into put_event(), this will
allow kernel space to create per-task inherited events, and is safer
in general.
Also, document the free_event() assumptions.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-rk9pvr6e1d0559lxstltbztc@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 38b435b16c ("perf: Fix tear-down of inherited group events")
states that we need to destroy groups for inherited events, but it
doesn't make any sense to not also destroy groups for normal events.
And while it usually makes no difference (the normal events won't
leak, and its very likely all the group events will die in quick
succession) it does make the code more consistent and closes a
potential hole for trouble.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-426egt8zmsm12d2q8k2xz4tt@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Make sure all events in a group have the same inherit state. It was
possible for group leaders to have inherit set while sibling events
would not have inherit set.
In this case we'd still inherit the siblings, leading to some
non-fatal weirdness.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-r32tt8yldvic3jlcghd3g35u@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When removing a (sibling) event we do:
raw_spin_lock_irq(&ctx->lock);
perf_group_detach(event);
raw_spin_unlock_irq(&ctx->lock);
<hole>
perf_remove_from_context(event);
raw_spin_lock_irq(&ctx->lock);
...
raw_spin_unlock_irq(&ctx->lock);
Now, assuming the event is a sibling, it will be 'unreachable' for
things like ctx_sched_out() because that iterates the
groups->siblings, and we just unhooked the sibling.
So, if during <hole> we get ctx_sched_out(), it will miss the event
and not call event_sched_out() on it, leaving it programmed on the
PMU.
The subsequent perf_remove_from_context() call will find the ctx is
inactive and only call list_del_event() to remove the event from all
other lists.
Hereafter we can proceed to free the event; while still programmed!
Close this hole by moving perf_group_detach() inside the same
ctx->lock region(s) perf_remove_from_context() has.
The condition on inherited events only in __perf_event_exit_task() is
likely complete crap because non-inherited events are part of groups
too and we're tearing down just the same. But leave that for another
patch.
Most-likely-Fixes: e03a9a55b4 ("perf: Change close() semantics for group events")
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Much-staring-at-traces-by: Vince Weaver <vincent.weaver@maine.edu>
Much-staring-at-traces-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140505093124.GN17778@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
valid_vma() rejects the VM_SHARED vmas, but this still allows to insert
a probe into the MAP_SHARED but not VM_MAYWRITE vma.
Currently this is fine, such a mapping doesn't really differ from the
private read-only mmap except mprotect(PROT_WRITE) won't work. However,
get_user_pages(FOLL_WRITE | FOLL_FORCE) doesn't allow to COW in this
case, and it would be safer to follow the same conventions as mm even
if currently this happens to work.
After the recent cda540ace6 "mm: get_user_pages(write,force) refuse
to COW in shared areas" only uprobes can insert an anon page into the
shared file-backed area, lets stop this and change valid_vma() to check
VM_MAYSHARE instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This patch adds support for building PMU driver as module. It exports
the functions perf_pmu_{register,unregister}() and adds reference tracking
for the PMU driver module.
When the PMU driver is built as a module, each active event of the PMU
holds a reference to the driver module.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1395133004-23205-1-git-send-email-zheng.z.yan@intel.com
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently the error from arch_uprobe_post_xol() is silently ignored.
This doesn't look good and this can lead to the hard-to-debug problems.
1. Change handle_singlestep() to loudly complain and send SIGILL.
Note: this only affects x86, ppc/arm can't fail.
2. Change arch_uprobe_post_xol() to call arch_uprobe_abort_xol() and
avoid TF games if it is going to return an error.
This can help to to analyze the problem, if nothing else we should
not report ->ip = xol_slot in the core-file.
Note: this means that handle_riprel_post_xol() can be called twice,
but this is fine because it is idempotent.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
UPROBE_COPY_INSN, UPROBE_SKIP_SSTEP, and uprobe->flags must die. This
patch kills UPROBE_SKIP_SSTEP. I never understood why it was added;
not only it doesn't help, it harms.
It can only help to avoid arch_uprobe_skip_sstep() if it was already
called before and failed. But this is ugly, if we want to know whether
we can emulate this instruction or not we should do this analysis in
arch_uprobe_analyze_insn(), not when we hit this probe for the first
time.
And in fact this logic is simply wrong. arch_uprobe_skip_sstep() can
fail or not depending on the task/register state, if this insn can be
emulated but, say, put_user() fails we need to xol it this time, but
this doesn't mean we shouldn't try to emulate it when this or another
thread hits this bp next time.
And this is the actual reason for this change. We need to emulate the
"call" insn, but push(return-address) can obviously fail.
Per-arch notes:
x86: __skip_sstep() can only emulate "rep;nop". With this
change it will be called every time and most probably
for no reason.
This will be fixed by the next changes. We need to
change this suboptimal code anyway.
arm: Should not be affected. It has its own "bool simulate"
flag checked in arch_uprobe_skip_sstep().
ppc: Looks like, it can emulate almost everything. Does it
actually need to record the fact that emulate_step()
failed? Hopefully not. But if yes, it can add the ppc-
specific flag into arch_uprobe.
TODO: rename arch_uprobe_skip_sstep() to arch_uprobe_emulate_insn(),
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Pull ARM changes from Russell King:
- Perf updates from Will Deacon:
- Support for Qualcomm Krait processors (run perf on your phone!)
- Support for Cortex-A12 (run perf stat on your FPGA!)
- Support for perf_sample_event_took, allowing us to automatically decrease
the sample rate if we can't handle the PMU interrupts quickly enough
(run perf record on your FPGA!).
- Basic uprobes support from David Long:
This patch series adds basic uprobes support to ARM. It is based on
patches developed earlier by Rabin Vincent. That approach of adding
hooks into the kprobes instruction parsing code was not well received.
This approach separates the ARM instruction parsing code in kprobes out
into a separate set of functions which can be used by both kprobes and
uprobes. Both kprobes and uprobes then provide their own semantic action
tables to process the results of the parsing.
- ARMv7M (microcontroller) updates from Uwe Kleine-König
- OMAP DMA updates (recently added Vinod's Ack even though they've been
sitting in linux-next for a few months) to reduce the reliance of
omap-dma on the code in arch/arm.
- SA11x0 changes from Dmitry Eremin-Solenikov and Alexander Shiyan
- Support for Cortex-A12 CPU
- Align support for ARMv6 with ARMv7 so they can cooperate better in a
single zImage.
- Addition of first AT_HWCAP2 feature bits for ARMv8 crypto support.
- Removal of IRQ_DISABLED from various ARM files
- Improved efficiency of virt_to_page() for single zImage
- Patch from Ulf Hansson to permit runtime PM callbacks to be available for
AMBA devices for suspend/resume as well.
- Finally kill asm/system.h on ARM.
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (89 commits)
dmaengine: omap-dma: more consolidation of CCR register setup
dmaengine: omap-dma: move IRQ handling to omap-dma
dmaengine: omap-dma: move register read/writes into omap-dma.c
ARM: omap: dma: get rid of 'p' allocation and clean up
ARM: omap: move dma channel allocation into plat-omap code
ARM: omap: dma: get rid of errata global
ARM: omap: clean up DMA register accesses
ARM: omap: remove almost-const variables
ARM: omap: remove references to disable_irq_lch
dmaengine: omap-dma: cleanup errata 3.3 handling
dmaengine: omap-dma: provide register read/write functions
dmaengine: omap-dma: use cached CCR value when enabling DMA
dmaengine: omap-dma: move barrier to omap_dma_start_desc()
dmaengine: omap-dma: move clnk_ctrl setting to preparation functions
dmaengine: omap-dma: improve efficiency loading C.SA/C.EI/C.FI registers
dmaengine: omap-dma: consolidate clearing channel status register
dmaengine: omap-dma: move CCR buffering disable errata out of the fast path
dmaengine: omap-dma: provide register definitions
dmaengine: omap-dma: consolidate setup of CCR
dmaengine: omap-dma: consolidate setup of CSDP
...
Pull cgroup updates from Tejun Heo:
"A lot updates for cgroup:
- The biggest one is cgroup's conversion to kernfs. cgroup took
after the long abandoned vfs-entangled sysfs implementation and
made it even more convoluted over time. cgroup's internal objects
were fused with vfs objects which also brought in vfs locking and
object lifetime rules. Naturally, there are places where vfs rules
don't fit and nasty hacks, such as credential switching or lock
dance interleaving inode mutex and cgroup_mutex with object serial
number comparison thrown in to decide whether the operation is
actually necessary, needed to be employed.
After conversion to kernfs, internal object lifetime and locking
rules are mostly isolated from vfs interactions allowing shedding
of several nasty hacks and overall simplification. This will also
allow implmentation of operations which may affect multiple cgroups
which weren't possible before as it would have required nesting
i_mutexes.
- Various simplifications including dropping of module support,
easier cgroup name/path handling, simplified cgroup file type
handling and task_cg_lists optimization.
- Prepatory changes for the planned unified hierarchy, which is still
a patchset away from being actually operational. The dummy
hierarchy is updated to serve as the default unified hierarchy.
Controllers which aren't claimed by other hierarchies are
associated with it, which BTW was what the dummy hierarchy was for
anyway.
- Various fixes from Li and others. This pull request includes some
patches to add missing slab.h to various subsystems. This was
triggered xattr.h include removal from cgroup.h. cgroup.h
indirectly got included a lot of files which brought in xattr.h
which brought in slab.h.
There are several merge commits - one to pull in kernfs updates
necessary for converting cgroup (already in upstream through
driver-core), others for interfering changes in the fixes branch"
* 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits)
cgroup: remove useless argument from cgroup_exit()
cgroup: fix spurious lockdep warning in cgroup_exit()
cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c
cgroup: break kernfs active_ref protection in cgroup directory operations
cgroup: fix cgroup_taskset walking order
cgroup: implement CFTYPE_ONLY_ON_DFL
cgroup: make cgrp_dfl_root mountable
cgroup: drop const from @buffer of cftype->write_string()
cgroup: rename cgroup_dummy_root and related names
cgroup: move ->subsys_mask from cgroupfs_root to cgroup
cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding
cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}()
cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root
cgroup: reorganize cgroup bootstrapping
cgroup: relocate setting of CGRP_DEAD
cpuset: use rcu_read_lock() to protect task_cs()
cgroup_freezer: document freezer_fork() subtleties
cgroup: update cgroup_transfer_tasks() to either succeed or fail
cgroup: drop task_lock() protection around task->cgroups
cgroup: update how a newly forked task gets associated with css_set
...
Allow arches to decided to ignore a probe hit. ARM will use this to
only call handlers if the conditions to execute a conditionally executed
instruction are satisfied.
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Use the ctx pmu instead of the event pmu.
When a group leader is a software event but the group contains
hardware events, the entire group is on the hardware PMU.
Using the hardware PMU for the transaction makes most sense since
that's the most expensive one to programm (and software PMUs generally
don't have TXN support anyway).
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-sctoo9t2f3nn2c9g568928q3@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently perf_branch_stack_sched_in iterates over the set of pmus,
checks that each pmu has a flush_branch_stack callback, then overwrites
the pmu before calling the callback. This is either redundant or broken.
In systems with a single hw pmu, pmu == cpuctx->ctx.pmu, and thus the
assignment is redundant.
In systems with multiple hw pmus (i.e. multiple pmus with task_ctx_nr ==
perf_hw_context) the pmus share the same perf_cpu_context. Thus the
assignment can cause one of the pmus to flush its branch stack
repeatedly rather than causing each of the pmus to flush their branch
stacks. Worse still, if only some pmus have the callback the assignment
can result in a branch to NULL.
This patch removes the redundant assignment.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1392054264-23570-3-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For some reason find_pmu_context() is defined as returning void * rather
than a __percpu struct perf_cpu_context *. As all the requisite types are
defined in advance there's no reason to keep it that way.
This patch modifies the prototype of pmu_find_context to return a
__percpu struct perf_cpu_context *.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1392054264-23570-2-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Drew Richardson reported that he could make the kernel go *boom* when hotplugging
while having perf events active.
It turned out that when you have a group event, the code in
__perf_event_exit_context() fails to remove the group siblings from
the context.
We then proceed with destroying and freeing the event, and when you
re-plug the CPU and try and add another event to that CPU, things go
*boom* because you've still got dead entries there.
Reported-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/n/tip-k6v5wundvusvcseqj1si0oz0@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Mon, Feb 10, 2014 at 08:45:16AM -0800, Dave Hansen wrote:
> The reason I coded this up was that NMIs were firing off so fast that
> nothing else was getting a chance to run. With this patch, at least the
> printk() would come out and I'd have some idea what was going on.
It will start spewing to early_printk() (which is a lot nicer to use
from NMI context too) when it fails to queue the IRQ-work because its
already enqueued.
It does have the false-positive for when two CPUs trigger the warn
concurrently, but that should be rare and some extra clutter on the
early printk shouldn't be a problem.
Cc: hpa@zytor.com
Cc: tglx@linutronix.de
Cc: dzickus@redhat.com
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: mingo@kernel.org
Fixes: 6a02ad66b2 ("perf/x86: Push the duration-logging printk() to IRQ context")
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140211150116.GO27965@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching
css. The intention of the interface is to make it easy to skip css's
(cgroup_subsys_states) which already match the migration target;
however, this is entirely unnecessary as migration taskset doesn't
include tasks which are already in the target cgroup. Drop @skip_css
from cgroup_taskset_for_each().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
css_from_dir() returns the matching css (cgroup_subsys_state) given a
dentry and subsystem. The function doesn't pin the css before
returning and requires the caller to be holding RCU read lock or
cgroup_mutex and handling pinning on the caller side.
Given that users of the function are likely to want to pin the
returned css (both existing users do) and that getting and putting
css's are very cheap, there's no reason for the interface to be tricky
like this.
Rename css_from_dir() to css_tryget_from_dir() and make it try to pin
the found css and return it only if pinning succeeded. The callers
are updated so that they no longer do RCU locking and pinning around
the function and just use the returned css.
This will also ease converting cgroup to kernfs.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Calling printk() from NMI context is bad (TM), so move it to IRQ
context.
This also avoids the problem where the printk() time is measured by
the generic NMI duration goo and triggers a second warning.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-75dv35xf6dhhmeb7nq6fua31@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
cgroup_subsys is a bit messier than it needs to be.
* The name of a subsys can be different from its internal identifier
defined in cgroup_subsys.h. Most subsystems use the matching name
but three - cpu, memory and perf_event - use different ones.
* cgroup_subsys_id enums are postfixed with _subsys_id and each
cgroup_subsys is postfixed with _subsys. cgroup.h is widely
included throughout various subsystems, it doesn't and shouldn't
have claim on such generic names which don't have any qualifier
indicating that they belong to cgroup.
* cgroup_subsys->subsys_id should always equal the matching
cgroup_subsys_id enum; however, we require each controller to
initialize it and then BUG if they don't match, which is a bit
silly.
This patch cleans up cgroup_subsys names and initialization by doing
the followings.
* cgroup_subsys_id enums are now postfixed with _cgrp_id, and each
cgroup_subsys with _cgrp_subsys.
* With the above, renaming subsys identifiers to match the userland
visible names doesn't cause any naming conflicts. All non-matching
identifiers are renamed to match the official names.
cpu_cgroup -> cpu
mem_cgroup -> memory
perf -> perf_event
* controllers no longer need to initialize ->subsys_id and ->name.
They're generated in cgroup core and set automatically during boot.
* Redundant cgroup_subsys declarations removed.
* While updating BUG_ON()s in cgroup_init_early(), convert them to
WARN()s. BUGging that early during boot is stupid - the kernel
can't print anything, even through serial console and the trap
handler doesn't even link stack frame properly for back-tracing.
This patch doesn't introduce any behavior changes.
v2: Rebased on top of fe1217c4f3 ("net: net_cls: move cgroupfs
classid handling into core").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Ingo Molnar <mingo@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
triggers by Tom Zanussi. A trigger is a way to enable an action when an
event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code.
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Merge tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This pull request has a new feature to ftrace, namely the trace event
triggers by Tom Zanussi. A trigger is a way to enable an action when
an event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code"
* tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (38 commits)
tracing: Fix buggered tee(2) on tracing_pipe
tracing: Have trace buffer point back to trace_array
ftrace: Fix synchronization location disabling and freeing ftrace_ops
ftrace: Have function graph only trace based on global_ops filters
ftrace: Synchronize setting function_trace_op with ftrace_trace_function
tracing: Show available event triggers when no trigger is set
tracing: Consolidate event trigger code
tracing: Fix counter for traceon/off event triggers
tracing: Remove double-underscore naming in syscall trigger invocations
tracing/kprobes: Add trace event trigger invocations
tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT
tracing/uprobes: Add @+file_offset fetch method
uprobes: Allocate ->utask before handler_chain() for tracing handlers
tracing/uprobes: Add support for full argument access methods
tracing/uprobes: Fetch args before reserving a ring buffer
tracing/uprobes: Pass 'is_return' to traceprobe_parse_probe_arg()
tracing/probes: Implement 'memory' fetch method for uprobes
tracing/probes: Add fetch{,_size} member into deref fetch method
tracing/probes: Move 'symbol' fetch method to kprobes
tracing/probes: Implement 'stack' fetch method for uprobes
...
Unlike recent modern userspace API such as:
epoll_create1 (EPOLL_CLOEXEC), eventfd (EFD_CLOEXEC),
fanotify_init (FAN_CLOEXEC), inotify_init1 (IN_CLOEXEC),
signalfd (SFD_CLOEXEC), timerfd_create (TFD_CLOEXEC),
or the venerable general purpose open (O_CLOEXEC),
perf_event_open() syscall lack a flag to atomically set FD_CLOEXEC
(eg. close-on-exec) flag on file descriptor it returns to userspace.
The present patch adds a PERF_FLAG_FD_CLOEXEC flag to allow
perf_event_open() syscall to atomically set close-on-exec.
Having this flag will enable userspace to remove the file descriptor
from the list of file descriptors being inherited across exec,
without the need to call fcntl(fd, F_SETFD, FD_CLOEXEC) and the
associated race condition between the current thread and another
thread calling fork(2) then execve(2).
Links:
- Secure File Descriptor Handling (Ulrich Drepper, 2008)
http://udrepper.livejournal.com/20407.html
- Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012)
http://danwalsh.livejournal.com/53603.html
- Notes in DMA buffer sharing: leak and security hole
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/dma-buf-sharing.txt?id=v3.13-rc3#n428
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch fixes a problem with the initialization of the
struct perf_event active_entry field. It is defined inside
an anonymous union and was initialized in perf_event_alloc()
using INIT_LIST_HEAD(). However at that time, we do not know
whether the event is going to use active_entry or hlist_entry (SW).
Or at last, we don't want to make that determination there.
The problem is that hlist and list_head are not initialized
the same way. One is okay with NULL (from kzmalloc), the other
needs to pointers to point to self.
This patch resolves this problem by dropping the union.
This will avoid problems later on, if someone starts using
active_entry or hlist_entry without verifying that they
actually overlap. This also solves the initialization
problem.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: vincent.weaver@maine.edu
Cc: maria.n.dimakopoulou@gmail.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389176153-3128-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
uprobe_trace_print() and uprobe_perf_print() need to pass the additional
info to call_fetch() methods, currently there is no simple way to do this.
current->utask looks like a natural place to hold this info, but we need
to allocate it before handler_chain().
This is a bit unfortunate, perhaps we will find a better solution later,
but this is simple and should work right now.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Vince Weaver reports that, on all architectures apart from ARM,
PERF_EVENT_IOC_PERIOD doesn't actually update the period until the next
event fires. This is counter-intuitive behaviour and is better dealt
with in the core code.
This patch ensures that the period is forcefully reset when dealing with
such a request in the core code. A subsequent patch removes the
equivalent hack from the ARM back-end.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1385560479-11014-1-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, only one PMU in a context gets disabled during unthrottling
and event_sched_{out,in}(), however, events in one context may belong to
different pmus, which results in PMUs being reprogrammed while they are
still enabled.
This means that mixed PMU use [which is rare in itself] resulted in
potentially completely unreliable results: corrupted events, bogus
results, etc.
This patch temporarily disables PMUs that correspond to
each event in the context while these events are being modified.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Remove a full barrier from the ring-buffer write path by relying on
a control dependency to order a LOAD -> STORE scenario.
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-8alv40z6ikk57jzbaobnxrjl@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds a new field to the struct perf_event.
It is intended to be used to chain events which are
active (enabled). It helps in the hardware layer
for PMUs which do not have actual counter restrictions, i.e.,
free running read-only counters. Active events are chained
as opposed to being tracked via the counter they use.
To save space we use a union with hlist_entry as both
are mutually exclusive (suggested by Jiri Olsa).
Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1384275531-10892-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. Don't include asm/uprobes.h unconditionally, we only need
it if CONFIG_UPROBES.
2. Move the definition of "struct xol_area" into uprobes.c.
Perhaps we should simply kill struct uprobes_state, it buys
nothing.
3. Kill the dummy definition of uprobe_get_swbp_addr(), nobody
except handle_swbp() needs it.
4. Purely cosmetic, but move the decl of uprobe_get_swbp_addr()
up, close to other __weak helpers.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
arch_uprobe should be opaque as much as possible to the generic
code, but currently it assumes that insn/ixol must be u8[] of the
known size. Remove this unnecessary dependency, we can use "&" and
and sizeof() with the same effect.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
uprobe_task->vaddr is a bit strange. The generic code uses it only
to pass the additional argument to arch_uprobe_pre_xol(), and since
it is always equal to instruction_pointer() this looks even more
strange.
And both utask->vaddr and and utask->autask have the same scope,
they only have the meaning when the task executes the probed insn
out-of-line, so it is safe to reuse both in UTASK_RUNNING state.
This all means that logically ->vaddr belongs to arch_uprobe_task
and we should probably move it there, arch_uprobe_pre_xol() can
record instruction_pointer() itself.
OTOH, it is also used by uprobe_copy_process() and dup_xol_work()
for another purpose, this doesn't look clean and doesn't allow to
move this member into arch_uprobe_task.
This patch adds the union with 2 anonymous structs into uprobe_task.
The first struct is autask + vaddr, this way we "almost" move vaddr
into autask.
The second struct has 2 new members for uprobe_copy_process() paths:
->dup_xol_addr which can be used instead ->vaddr, and ->dup_xol_work
which can be used to avoid kmalloc() and simplify the code.
Note that this union will likely have another member(s), we need
something like "private_data_for_handlers" so that the tracing
handlers could use it to communicate with call_fetch() methods.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Currently we only allocate a single cpu hashtable for per-cpu
swevents; do away with this optimization for it is fragile in the face
of things like perf_pmu_migrate_context().
The easiest thing is to make sure all CPUs are consistent wrt state.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130913111447.GN31370@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add two trivial helpers list_next_entry() and list_prev_entry(), they
can have a lot of users including list.h itself. In fact the 1st one is
already defined in events/core.c and bnx2x_sp.c, so the patch simply
moves the definition to list.h.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1. copy_insn() doesn't look very nice, all calculations are
confusing and it is not immediately clear why do we read
the 2nd page first.
2. The usage of inode->i_size is wrong on 32-bit machines.
3. "Instruction at end of binary" logic is simply wrong, it
doesn't handle the case when uprobe->offset > inode->i_size.
In this case "bytes" overflows, and __copy_insn() writes to
the memory outside of uprobe->arch.insn.
Yes, uprobe_register() checks i_size_read(), but this file
can be truncated after that. All i_size checks are racy, we
do this only to catch the obvious mistakes.
Change copy_insn() to call __copy_insn() in a loop, simplify
and fix the bytes/nbytes calculations.
Note: we do not care if we read extra bytes after inode->i_size
if we got the valid page. This is fine because the task gets the
same page after page-fault, and arch_uprobe_analyze_insn() can't
know how many bytes were actually read anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Commit aa59c53fd4 "uprobes: Change uprobe_copy_process() to dup
xol_area" has a stupid typo, we need to setup t->utask->vaddr but
the code wrongly uses current->utask.
Even with this bug dup_xol_work() works "in practice", but only
because get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE) likely
returns the same address every time.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Here's the big driver core / sysfs update for 3.13-rc1.
There's lots of dev_groups updates for different subsystems, as they all
get slowly migrated over to the safe versions of the attribute groups
(removing userspace races with the creation of the sysfs files.) Also
in here are some kobject updates, devres expansions, and the first round
of Tejun's sysfs reworking to enable it to be used by other subsystems
as a backend for an in-kernel filesystem.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core / sysfs patches from Greg KH:
"Here's the big driver core / sysfs update for 3.13-rc1.
There's lots of dev_groups updates for different subsystems, as they
all get slowly migrated over to the safe versions of the attribute
groups (removing userspace races with the creation of the sysfs
files.) Also in here are some kobject updates, devres expansions, and
the first round of Tejun's sysfs reworking to enable it to be used by
other subsystems as a backend for an in-kernel filesystem.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (83 commits)
sysfs: rename sysfs_assoc_lock and explain what it's about
sysfs: use generic_file_llseek() for sysfs_file_operations
sysfs: return correct error code on unimplemented mmap()
mdio_bus: convert bus code to use dev_groups
device: Make dev_WARN/dev_WARN_ONCE print device as well as driver name
sysfs: separate out dup filename warning into a separate function
sysfs: move sysfs_hash_and_remove() to fs/sysfs/dir.c
sysfs: remove unused sysfs_get_dentry() prototype
sysfs: honor bin_attr.attr.ignore_lockdep
sysfs: merge sysfs_elem_bin_attr into sysfs_elem_attr
devres: restore zeroing behavior of devres_alloc()
sysfs: fix sysfs_write_file for bin file
input: gameport: convert bus code to use dev_groups
input: serio: remove bus usage of dev_attrs
input: serio: use DEVICE_ATTR_RO()
i2o: convert bus code to use dev_groups
memstick: convert bus code to use dev_groups
tifm: convert bus code to use dev_groups
virtio: convert bus code to use dev_groups
ipack: convert bus code to use dev_groups
...
set_swbp() and set_orig_insn() are __weak, but this is pointless
because write_opcode() is static.
Export write_opcode() as uprobe_write_opcode() for the upcoming
arm port, this way it can actually override set_swbp() and use
__opcode_to_mem_arm(bpinsn) instead if UPROBE_SWBP_INSN.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Currently xol_get_insn_slot() assumes that we should simply copy
arch_uprobe->insn[] which is (ignoring arch_uprobe_analyze_insn)
just the copy of the original insn.
This is not true for arm which needs to create another insn to
execute it out-of-line.
So this patch simply adds the new member, ->ixol into the union.
This doesn't make any difference for x86 and powerpc, but arm
can divorce insn/ixol and initialize the correct xol insn in
arch_uprobe_analyze_insn().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Turn module_init() into __initcall() and kill module_exit().
This code can't be compiled as a module so these module_*()
calls only add the confusion, especially if arch-dependant
code needs its own initialization hooks.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
While this is really minor, but strncpy() does the unnecessary
zero-padding till the end of tmp[16] and it is called every time
we are going to use the string literal.
Turn these strncpy()'s into the single strlcpy() under the new
label, saves 72 bytes.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131017182417.GA17753@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The arch_perf_output_copy_user() default of
__copy_from_user_inatomic() returns bytes not copied, while all other
argument functions given DEFINE_OUTPUT_COPY() return bytes copied.
Since copy_from_user_nmi() is the odd duck out by returning bytes
copied where all other *copy_{to,from}* functions return bytes not
copied, change it over and ammend DEFINE_OUTPUT_COPY() to expect bytes
not copied.
Oddly enough DEFINE_OUTPUT_COPY() already returned bytes not copied
while expecting its worker functions to return bytes copied.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: will.deacon@arm.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131030201622.GR16117@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Avoid touching the lost_event and sample_data cachelines twince. Its
not like we end up doing less work, but it might help to keep all
accesses to these cachelines in one place.
Due to code shuffle, this looses 4 bytes on x86_64-defconfig.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-zfxnc58qxj0eawdoj31hhupv@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There's no point in re-doing the memory-barrier when we fail the
cmpxchg(). Also placing it after the space reservation loop makes it
clearer it only separates the userpage->tail read from the data
stores.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-c19u6egfldyx86tpyc3zgkw9@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add unlikely() annotations to 'slow' paths:
When having a sampling event but no output buffer; you have bigger
issues -- also the bail is still faster than actually doing the work.
When having a sampling event but a control page only buffer, you have
bigger issues -- again the bail is still faster than actually doing
work.
Optimize for the case where you're not loosing events -- again, not
doing the work is still faster but make sure that when you have to
actually do work its as fast as possible.
The typical watermark is 1/2 the buffer size, so most events will not
take this path.
Shrinks perf_output_begin() by 16 bytes on x86_64-defconfig.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-wlg3jew3qnutm8opd0hyeuwn@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
By using CIRC_SPACE() we can obviate the need for perf_output_space().
Shrinks the size of perf_output_begin() by 17 bytes on
x86_64-defconfig.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-vtb0xb0llebmsdlfn1v5vtfj@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
uprobe_copy_process() does nothing if the child shares ->mm with
the forking process, but there is a special case: CLONE_VFORK.
In this case it would be more correct to do dup_utask() but avoid
dup_xol(). This is not that important, the child should not unwind
its stack too much, this can corrupt the parent's stack, but at
least we need this to allow to ret-probe __vfork() itself.
Note: in theory, it would be better to check task_pt_regs(p)->sp
instead of CLONE_VFORK, we need to dup_utask() if and only if the
child can return from the function called by the parent. But this
needs the arch-dependant helper, and I think that nobody actually
does clone(same_stack, CLONE_VM).
Reported-by: Martin Cermak <mcermak@redhat.com>
Reported-by: David Smith <dsmith@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This finally fixes the serious bug in uretprobes: a forked child
crashes if the parent called fork() with the pending ret probe.
Trivial test-case:
# perf probe -x /lib/libc.so.6 __fork%return
# perf record -e probe_libc:__fork perl -le 'fork || print "OK"'
(the child doesn't print "OK", it is killed by SIGSEGV)
If the child returns from the probed function it actually returns
to trampoline_vaddr, because it got the copy of parent's stack
mangled by prepare_uretprobe() when the parent entered this func.
It crashes because a) this address is not mapped and b) until the
previous change it doesn't have the proper->return_instances info.
This means that uprobe_copy_process() has to create xol_area which
has the trampoline slot, and its vaddr should be equal to parent's
xol_area->vaddr.
Unfortunately, uprobe_copy_process() can not simply do
__create_xol_area(child, xol_area->vaddr). This could actually work
but perf_event_mmap() doesn't expect the usage of foreign ->mm. So
we offload this to task_work_run(), and pass the argument via not
yet used utask->vaddr.
We know that this vaddr is fine for install_special_mapping(), the
necessary hole was recently "created" by dup_mmap() which skips the
parent's VM_DONTCOPY area, and nobody else could use the new mm.
Unfortunately, this also means that we can not handle the errors
properly, we obviously can not abort the already completed fork().
So we simply print the warning if GFP_KERNEL allocation (the only
possible reason) fails.
Reported-by: Martin Cermak <mcermak@redhat.com>
Reported-by: David Smith <dsmith@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
uprobe_copy_process() assumes that the new child doesn't need
->utask, it should be allocated by demand.
But this is not true if the forking task has the pending ret-
probes, the child should report them as well and thus it needs
the copy of parent's ->return_instances chain. Otherwise the
child crashes when it returns from the probed function.
Alternatively we could cleanup the child's stack, but this needs
per-arch changes and this is not what we want. At least systemtap
expects a .return in the child too.
Note: this change alone doesn't fix the problem, see the next
change.
Reported-by: Martin Cermak <mcermak@redhat.com>
Reported-by: David Smith <dsmith@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Currently xol_add_vma() uses get_unmapped_area() for area->vaddr,
but the next patches need to use the fixed address. So this patch
adds the new "vaddr" argument to __create_xol_area() which should
be used as area->vaddr if it is nonzero.
xol_add_vma() doesn't bother to verify that the predefined addr is
not used, insert_vm_struct() should fail if find_vma_links() detects
the overlap with the existing vma.
Also, __create_xol_area() doesn't need __GFP_ZERO to allocate area.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
No functional changes, preparation.
Extract the code which actually allocates/installs the new area
into the new helper, __create_xol_area().
While at it remove the unnecessary "ret = ENOMEM" and "ret = 0"
in xol_add_vma(), they both have no effect.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Preparation for the next patches.
Move the callsite of uprobe_copy_process() in copy_process() down
to the succesfull return. We do not care if copy_process() fails,
uprobe_free_utask() won't be called in this case so the wrong
->utask != NULL doesn't matter.
OTOH, with this change we know that copy_process() can't fail when
uprobe_copy_process() is called, the new task should either return
to user-mode or call do_exit(). This way uprobe_copy_process() can:
1. setup p->utask != NULL if necessary
2. setup uprobes_state.xol_area
3. use task_work_add(p)
Also, move the definition of uprobe_copy_process() down so that it
can see get_utask().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Currently we only optimize the context switch between two
contexts that have the same parent; this forgoes the
optimization between parent and child context, even though these
contexts could be equivalent too.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Shishkin, Alexander <alexander.shishkin@intel.com>
Link: http://lkml.kernel.org/r/20131007164257.GH3081@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Oleg complained about the excessive 0-ing in perf_event_mmap_event(),
so try and be smarter about it while keeping it fairly fool proof and
avoid leaking random bits out to userspace.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-8jirlm99m6if2z13wd6rbyu6@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_event_mmap_event() does kzalloc(PATH_MAX + sizeof(u64)) to
ensure we can align the size later. However this means that we
actually allocate PAGE_SIZE * 2 buffer, seems too much.
Change this code to allocate PATH_MAX==PAGE_SIZE bytes, but tell
d_path() to not use the last sizeof(u64) bytes.
Note: it is not clear why do we need __GFP_ZERO, see the next patch.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131016201004.GC23214@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. perf_event_mmap(vma) is never called with a gate_vma-like arg,
remove the "if (!vma->vm_mm)" code.
2. arch_vma_name() can use the chached value of mmap_event->vma.
3. Change the code to not call arch_vma_name() twice.
4. Purely cosmetic, but since we use "goto got_name" all the time
remove "else" from "[stack]" branch just for symmetry.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131016200945.GB23214@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The PPC64 people noticed a missing memory barrier and crufty old
comments in the perf ring buffer code. So update all the comments and
add the missing barrier.
When the architecture implements local_t using atomic_long_t there
will be double barriers issued; but short of introducing more
conditional barrier primitives this is the best we can do.
Reported-by: Victor Kaplansky <victork@il.ibm.com>
Tested-by: Victor Kaplansky <victork@il.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: michael@ellerman.id.au
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: anton@samba.org
Cc: benh@kernel.crashing.org
Link: http://lkml.kernel.org/r/20131025173749.GG19466@laptop.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For now, we disable the extended MMAP record support (MMAP2).
We have identified cases where it would not report the correct mapping
information, clone(VM_CLONE) but with separate pids. We will revisit
the support once we find a solution for this case.
The patch changes the kernel to return EINVAL if attr->mmap2 is set. The
patch also modifies the perf tool to use regular PERF_RECORD_MMAP for
synthetic events and it also prevents the tool from requesting
attr->mmap2 mode because the kernel would reject it.
The support will be revisited once the kenrel interface is updated.
In V2, we reduce the patch to the strict minimum.
In V3, we avoid calling perf_event_open() with mmap2 set because we know
it will fail and require fallback retry.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131017173215.GA8820@quad
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a generic qualifier for transaction events, as a new sample
type that returns a flag word. This is particularly useful
for qualifying aborts: to distinguish aborts which happen
due to asynchronous events (like conflicts caused by another
CPU) versus instructions that lead to an abort.
The tuning strategies are very different for those cases,
so it's important to distinguish them easily and early.
Since it's inconvenient and inflexible to filter for this
in the kernel we report all the events out and allow
some post processing in user space.
The flags are based on the Intel TSX events, but should be fairly
generic and mostly applicable to other HTM architectures too. In addition
to various flag words there's also reserved space to report an
program supplied abort code. For TSX this is used to distinguish specific
classes of aborts, like a lock busy abort when doing lock elision.
Flags:
Elision and generic transactions (ELISION vs TRANSACTION)
(HLE vs RTM on TSX; IBM etc. would likely only use TRANSACTION)
Aborts caused by current thread vs aborts caused by others (SYNC vs ASYNC)
Retryable transaction (RETRY)
Conflicts with other threads (CONFLICT)
Transaction write capacity overflow (CAPACITY WRITE)
Transaction read capacity overflow (CAPACITY READ)
Transactions implicitely aborted can also return an abort code.
This can be used to signal specific events to the profiler. A common
case is abort on lock busy in a RTM eliding library (code 0xff)
To handle this case we include the TSX abort code
Common example aborts in TSX would be:
- Data conflict with another thread on memory read.
Flags: TRANSACTION|ASYNC|CONFLICT
- executing a WRMSR in a transaction. Flags: TRANSACTION|SYNC
- HLE transaction in user space is too large
Flags: ELISION|SYNC|CAPACITY-WRITE
The only flag that is somewhat TSX specific is ELISION.
This adds the perf core glue needed for reporting the new flag word out.
v2: Add MEM/MISC
v3: Move transaction to the end
v4: Separate capacity-read/write and remove misc
v5: Remove _SAMPLE. Move abort flags to 32bit. Rename
transaction to txn
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1379688044-14173-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
/proc/sys/kernel/perf_event_max_sample_rate will accept
negative values as well as 0.
Negative values are unreasonable, and 0 causes a
divide by zero exception in perf_proc_update_handler.
This patch enforces a lower limit of 1.
Signed-off-by: Knut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While auditing the list_entry usage due to a trinity bug I found that
perf_pmu_migrate_context violates the rules for
perf_event::event_entry.
The problem is that perf_event::event_entry is a RCU list element, and
hence we must wait for a full RCU grace period before re-using the
element after deletion.
Therefore the usage in perf_pmu_migrate_context() which re-uses the
entry immediately is broken. For now introduce another list_head into
perf_event for this specific usage.
This doesn't actually fix the trinity report because that never goes
through this code.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-mkj72lxagw1z8fvjm648iznw@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The dev_attrs field of struct bus_type is going away soon, dev_groups
should be used instead. This converts the pmu bus code to use
the correct field.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Solve the problems around the broken definition of perf_event_mmap_page::
cap_usr_time and cap_usr_rdpmc fields which used to overlap, partially
fixed by:
860f085b74 ("perf: Fix broken union in 'struct perf_event_mmap_page'")
The problem with the fix (merged in v3.12-rc1 and not yet released
officially), noticed by Vince Weaver is that the new behavior is
not detectable by new user-space, and that due to the reuse of the
field names it's easy to mis-compile a binary if old headers are used
on a new kernel or new headers are used on an old kernel.
To solve all that make this change explicit, detectable and self-contained,
by iterating the ABI the following way:
- Always clear bit 0, and rename it to usrpage->cap_bit0, to at least not
confuse old user-space binaries. RDPMC will be marked as unavailable
to old binaries but that's within the ABI, this is a capability bit.
- Rename bit 1 to ->cap_bit0_is_deprecated and always set it to 1, so new
libraries can reliably detect that bit 0 is deprecated and perma-zero
without having to check the kernel version.
- Use bits 2, 3, 4 for the newly defined, correct functionality:
cap_user_rdpmc : 1, /* The RDPMC instruction can be used to read counts */
cap_user_time : 1, /* The time_* fields are used */
cap_user_time_zero : 1, /* The time_zero field is used */
- Rename all the bitfield names in perf_event.h to be different from the
old names, to make sure it's not possible to mis-compile it
accidentally with old assumptions.
The 'size' field can then be used in the future to add new fields and it
will act as a natural ABI version indicator as well.
Also adjust tools/perf/ userspace for the new definitions, noticed by
Adrian Hunter.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Also-Fixed-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/n/tip-zr03yxjrpXesOzzupszqglbv@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently utask->depth is simply the number of allocated/pending
return_instance's in uprobe_task->return_instances list.
handle_trampoline() should decrement this counter every time we
handle/free an instance, but due to typo it does this only if
->chained == T. This means that in the likely case this counter
is never decremented and the probed task can't report more than
MAX_URETPROBE_DEPTH events.
Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com>
Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Cc: masami.hiramatsu.pt@hitachi.com
Cc: srikar@linux.vnet.ibm.com
Cc: systemtap@sourceware.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20130911154726.GA8093@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf changes from Ingo Molnar:
"As a first remark I'd like to point out that the obsolete '-f'
(--force) option, which has not done anything for several releases,
has been removed from 'perf record' and related utilities. Everyone
please update muscle memory accordingly! :-)
Main changes on the perf kernel side:
- Performance optimizations:
. for trace events, by Steve Rostedt.
. for time values, by Peter Zijlstra
- New hardware support:
. for Intel Silvermont (22nm Atom) CPUs, by Zheng Yan
. for Intel SNB-EP uncore PMUs, by Zheng Yan
- Enhanced hardware support:
. for Intel uncore PMUs: add filter support for QPI boxes, by Zheng Yan
- Core perf events code enhancements and fixes:
. for full-nohz feature handling, by Frederic Weisbecker
. for group events, by Jiri Olsa
. for call chains, by Frederic Weisbecker
. for event stream parsing, by Adrian Hunter
- New ABI details:
. Add attr->mmap2 attribute, by Stephane Eranian
. Add PERF_EVENT_IOC_ID ioctl to return event ID, by Jiri Olsa
. Export u64 time_zero on the mmap header page to allow TSC
calculation, by Adrian Hunter
. Add dummy software event, by Adrian Hunter.
. Add a new PERF_SAMPLE_IDENTIFIER to make samples always
parseable, by Adrian Hunter.
. Make Power7 events available via sysfs, by Runzhen Wang.
- Code cleanups and refactorings:
. for nohz-full, by Frederic Weisbecker
. for group events, by Jiri Olsa
- Documentation updates:
. for perf_event_type, by Peter Zijlstra
Main changes on the perf tooling side (some of these tooling changes
utilize the above kernel side changes):
- Lots of 'perf trace' enhancements:
. Make 'perf trace' command line arguments consistent with
'perf record', by David Ahern.
. Allow specifying syscalls a la strace, by Arnaldo Carvalho de Melo.
. Add --verbose and -o/--output options, by Arnaldo Carvalho de Melo.
. Support ! in -e expressions, to filter a list of syscalls,
by Arnaldo Carvalho de Melo.
. Arg formatting improvements to allow masking arguments in
syscalls such as futex and open, where the some arguments are
ignored and thus should not be printed depending on other args,
by Arnaldo Carvalho de Melo.
. Beautify futex open, openat, open_by_handle_at, lseek and futex
syscalls, by Arnaldo Carvalho de Melo.
. Add option to analyze events in a file versus live, so that
one can do:
[root@zoo ~]# perf record -a -e raw_syscalls:* sleep 1
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 25.150 MB perf.data (~1098836 samples) ]
[root@zoo ~]# perf trace -i perf.data -e futex --duration 1
17.799 ( 1.020 ms): 7127 futex(uaddr: 0x7fff3f6c6674, op: 393, val: 1, utime: 0x7fff3f6c6470, ua
113.344 (95.429 ms): 7127 futex(uaddr: 0x7fff3f6c6674, op: 393, val: 1, utime: 0x7fff3f6c6470, uaddr2: 0x7fff3f6c6648, val3: 4294967
133.778 ( 1.042 ms): 18004 futex(uaddr: 0x7fff3f6c6674, op: 393, val: 1, utime: 0x7fff3f6c6470, uaddr2: 0x7fff3f6c6648, val3: 429496
[root@zoo ~]#
By David Ahern.
. Honor target pid / tid options when analyzing a file, by David Ahern.
. Introduce better formatting of syscall arguments, including so
far beautifiers for mmap, madvise, syscall return values,
by Arnaldo Carvalho de Melo.
. Handle HUGEPAGE defines in the mmap beautifier, by David Ahern.
- 'perf report/top' enhancements:
. Do annotation using /proc/kcore and /proc/kallsyms when
available, removing the forced need for a vmlinux file kernel
assembly annotation. This also improves this use case because
vmlinux has just the initial kernel image, not what is actually
in use after various code patchings by things like alternatives.
By Adrian Hunter.
. Add --ignore-callees=<regex> option to collapse undesired parts
of call graphs, by Greg Price.
. Simplify symbol filtering by doing it at machine class level,
by Adrian Hunter.
. Add support for callchains in the gtk UI, by Namhyung Kim.
. Add --objdump option to 'perf top', by Sukadev Bhattiprolu.
- 'perf kvm' enhancements:
. Add option to print only events that exceed a specified time
duration, by David Ahern.
. Improve stack trace printing, by David Ahern.
. Update documentation of the live command, by David Ahern
. Add perf kvm stat live mode that combines aspects of 'perf kvm
stat' record and report, by David Ahern.
. Add option to analyze specific VM in perf kvm stat report, by
David Ahern.
. Do not require /lib/modules/* on a guest, by Jason Wessel.
- 'perf script' enhancements:
. Fix symbol offset computation for some dsos, by David Ahern.
. Fix named threads support, by David Ahern.
. Don't install scripting files files when perl/python support
is disabled, by Arnaldo Carvalho de Melo.
- 'perf test' enhancements:
. Add various improvements and fixes to the "vmlinux matches
kallsyms" 'perf test' entry, related to the /proc/kcore
annotation feature. By Adrian Hunter.
. Add sample parsing test, by Adrian Hunter.
. Add test for reading object code, by Adrian Hunter.
. Add attr record group sampling test, by Jiri Olsa.
. Misc testing infrastructure improvements and other details,
by Jiri Olsa.
- 'perf list' enhancements:
. Skip unsupported hardware events, by Namhyung Kim.
. List pmu events, by Andi Kleen.
- 'perf diff' enhancements:
. Add support for more than two files comparison, by Jiri Olsa.
- 'perf sched' enhancements:
. Various improvements, including removing reliance on some
scheduler tracepoints that provide the same information as the
PERF_RECORD_{FORK,EXIT} events. By David Ahern.
. Remove odd build stall by moving a large struct initialization
from a local variable to a global one, by Namhyung Kim.
- 'perf stat' enhancements:
. Add --initial-delay option to skip measuring for a defined
startup phase, by Andi Kleen.
- Generic perf tooling infrastructure/plumbing changes:
. Tidy up sample parsing validation, by Adrian Hunter.
. Fix up jobserver setup in libtraceevent Makefile.
by Arnaldo Carvalho de Melo.
. Debug improvements, by Adrian Hunter.
. Fix correlation of samples coming after PERF_RECORD_EXIT event,
by David Ahern.
. Improve robustness of the topology parsing code,
by Stephane Eranian.
. Add group leader sampling, that allows just one event in a group
to sample while the other events have just its values read,
by Jiri Olsa.
. Add support for a new modifier "D", which requests that the
event, or group of events, be pinned to the PMU.
By Michael Ellerman.
. Support callchain sorting based on addresses, by Andi Kleen
. Prep work for multi perf data file storage, by Jiri Olsa.
. libtraceevent cleanups, by Namhyung Kim.
And lots and lots of other fixes and code reorganizations that did not
make it into the list, see the shortlog, diffstat and the Git log for
details!"
[ Also merge a leftover from the 3.11 cycle ]
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Prevent race in unthrottling code
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (237 commits)
perf trace: Tell arg formatters the arg index
perf trace: Add beautifier for open's flags arg
perf trace: Add beautifier for lseek's whence arg
perf tools: Fix symbol offset computation for some dsos
perf list: Skip unsupported events
perf tests: Add 'keep tracking' test
perf tools: Add support for PERF_COUNT_SW_DUMMY
perf: Add a dummy software event to keep tracking
perf trace: Add beautifier for futex 'operation' parm
perf trace: Allow syscall arg formatters to mask args
perf: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node()
perf: Export struct perf_branch_entry to userspace
perf: Add attr->mmap2 attribute to an event
perf/x86: Add Silvermont (22nm Atom) support
perf/x86: use INTEL_UEVENT_EXTRA_REG to define MSR_OFFCORE_RSP_X
perf trace: Handle missing HUGEPAGE defines
perf trace: Honor target pid / tid options when analyzing a file
perf trace: Add option to analyze events in a file versus live
perf evlist: Add tracepoint lookup by name
perf tests: Add a sample parsing test
...
Pull cgroup updates from Tejun Heo:
"A lot of activities on the cgroup front. Most changes aren't visible
to userland at all at this point and are laying foundation for the
planned unified hierarchy.
- The biggest change is decoupling the lifetime management of css
(cgroup_subsys_state) from that of cgroup's. Because controllers
(cpu, memory, block and so on) will need to be dynamically enabled
and disabled, css which is the association point between a cgroup
and a controller may come and go dynamically across the lifetime of
a cgroup. Till now, css's were created when the associated cgroup
was created and stayed till the cgroup got destroyed.
Assumptions around this tight coupling permeated through cgroup
core and controllers. These assumptions are gradually removed,
which consists bulk of patches, and css destruction path is
completely decoupled from cgroup destruction path. Note that
decoupling of creation path is relatively easy on top of these
changes and the patchset is pending for the next window.
- cgroup has its own event mechanism cgroup.event_control, which is
only used by memcg. It is overly complex trying to achieve high
flexibility whose benefits seem dubious at best. Going forward,
new events will simply generate file modified event and the
existing mechanism is being made specific to memcg. This pull
request contains prepatory patches for such change.
- Various fixes and cleanups"
Fixed up conflict in kernel/cgroup.c as per Tejun.
* 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (69 commits)
cgroup: fix cgroup_css() invocation in css_from_id()
cgroup: make cgroup_write_event_control() use css_from_dir() instead of __d_cgrp()
cgroup: make cgroup_event hold onto cgroup_subsys_state instead of cgroup
cgroup: implement CFTYPE_NO_PREFIX
cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys
cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax
cgroup: fix cgroup_write_event_control()
cgroup: fix subsystem file accesses on the root cgroup
cgroup: change cgroup_from_id() to css_from_id()
cgroup: use css_get() in cgroup_create() to check CSS_ROOT
cpuset: remove an unncessary forward declaration
cgroup: RCU protect each cgroup_subsys_state release
cgroup: move subsys file removal to kill_css()
cgroup: factor out kill_css()
cgroup: decouple cgroup_subsys_state destruction from cgroup destruction
cgroup: replace cgroup->css_kill_cnt with ->nr_css
cgroup: bounce cgroup_subsys_state ref kill confirmation to a work item
cgroup: move cgroup->subsys[] assignment to online_css()
cgroup: reorganize css init / exit paths
cgroup: add __rcu modifier to cgroup->subsys[]
...
Adds a new PERF_RECORD_MMAP2 record type which is essence
an expanded version of PERF_RECORD_MMAP.
Used to request mmap records with more information about
the mapping, including device major, minor and the inode
number and generation for mappings associated with files
or shared memory segments. Works for code and data
(with attr->mmap_data set).
Existing PERF_RECORD_MMAP record is unmodified by this patch.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/1377079825-19057-2-git-send-email-eranian@google.com
[ Added Al to the Cc:. Are the ino, maj/min exports of vma->vm_file OK? ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current throttling code triggers WARN below via following
workload (only hit on AMD machine with 48 CPUs):
# while [ 1 ]; do perf record perf bench sched messaging; done
WARNING: at arch/x86/kernel/cpu/perf_event.c:1054 x86_pmu_start+0xc6/0x100()
SNIP
Call Trace:
<IRQ> [<ffffffff815f62d6>] dump_stack+0x19/0x1b
[<ffffffff8105f531>] warn_slowpath_common+0x61/0x80
[<ffffffff8105f60a>] warn_slowpath_null+0x1a/0x20
[<ffffffff810213a6>] x86_pmu_start+0xc6/0x100
[<ffffffff81129dd2>] perf_adjust_freq_unthr_context.part.75+0x182/0x1a0
[<ffffffff8112a058>] perf_event_task_tick+0xc8/0xf0
[<ffffffff81093221>] scheduler_tick+0xd1/0x140
[<ffffffff81070176>] update_process_times+0x66/0x80
[<ffffffff810b9565>] tick_sched_handle.isra.15+0x25/0x60
[<ffffffff810b95e1>] tick_sched_timer+0x41/0x60
[<ffffffff81087c24>] __run_hrtimer+0x74/0x1d0
[<ffffffff810b95a0>] ? tick_sched_handle.isra.15+0x60/0x60
[<ffffffff81088407>] hrtimer_interrupt+0xf7/0x240
[<ffffffff81606829>] smp_apic_timer_interrupt+0x69/0x9c
[<ffffffff8160569d>] apic_timer_interrupt+0x6d/0x80
<EOI> [<ffffffff81129f74>] ? __perf_event_task_sched_in+0x184/0x1a0
[<ffffffff814dd937>] ? kfree_skbmem+0x37/0x90
[<ffffffff815f2c47>] ? __slab_free+0x1ac/0x30f
[<ffffffff8118143d>] ? kfree+0xfd/0x130
[<ffffffff81181622>] kmem_cache_free+0x1b2/0x1d0
[<ffffffff814dd937>] kfree_skbmem+0x37/0x90
[<ffffffff814e03c4>] consume_skb+0x34/0x80
[<ffffffff8158b057>] unix_stream_recvmsg+0x4e7/0x820
[<ffffffff814d5546>] sock_aio_read.part.7+0x116/0x130
[<ffffffff8112c10c>] ? __perf_sw_event+0x19c/0x1e0
[<ffffffff814d5581>] sock_aio_read+0x21/0x30
[<ffffffff8119a5d0>] do_sync_read+0x80/0xb0
[<ffffffff8119ac85>] vfs_read+0x145/0x170
[<ffffffff8119b699>] SyS_read+0x49/0xa0
[<ffffffff810df516>] ? __audit_syscall_exit+0x1f6/0x2a0
[<ffffffff81604a19>] system_call_fastpath+0x16/0x1b
---[ end trace 622b7e226c4a766a ]---
The reason is a race in perf_event_task_tick() throttling code.
The race flow (simplified code):
- perf_throttled_count is per cpu variable and is
CPU throttling flag, here starting with 0
- perf_throttled_seq is sequence/domain for allowed
count of interrupts within the tick, gets increased
each tick
on single CPU (CPU bounded event):
... workload
perf_event_task_tick:
|
| T0 inc(perf_throttled_seq)
| T1 needs_unthr = xchg(perf_throttled_count, 0) == 0
tick gets interrupted:
... event gets throttled under new seq ...
T2 last NMI comes, event is throttled - inc(perf_throttled_count)
back to tick:
| perf_adjust_freq_unthr_context:
|
| T3 unthrottling is skiped for event (needs_unthr == 0)
| T4 event is stop and started via freq adjustment
|
tick ends
... workload
... no sample is hit for event ...
perf_event_task_tick:
|
| T5 needs_unthr = xchg(perf_throttled_count, 0) != 0 (from T2)
| T6 unthrottling is done on event (interrupts == MAX_INTERRUPTS)
| event is already started (from T4) -> WARN
Fixing this by not checking needs_unthr again and thus
check all events for unthrottling.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1377355554-8934-1-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The event stream is not always parsable because the format of a sample
is dependent on the sample_type of the selected event. When there is
more than one selected event and the sample_types are not the same then
parsing becomes problematic. A sample can be matched to its selected
event using the ID that is allocated when the event is opened.
Unfortunately, to get the ID from the sample means first parsing it.
This patch adds a new sample format bit PERF_SAMPLE_IDENTIFER that puts
the ID at a fixed position so that the ID can be retrieved without
parsing the sample. For sample events, that is the first position
immediately after the header. For non-sample events, that is the last
position.
In this respect parsing samples requires that the sample_type and ID
values are recorded. For example, perf tools records struct
perf_event_attr and the IDs within the perf.data file. Those must be
read first before it is possible to parse samples found later in the
perf.data file.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1377591794-30553-6-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
cgroup_css_from_dir() will grow another user. In preparation, make
the following changes.
* All css functions are prefixed with just "css_", rename it to
css_from_dir().
* Take dentry * instead of file * as dentry is what ultimately
identifies a cgroup and file may not always be available. Note that
the function now checkes whether @dentry->d_inode is NULL as the
caller now may specify a negative dentry.
* Make it take cgroup_subsys * instead of integer subsys_id. This
simplifies the function and allows specifying no subsystem for
cgroup->dummy_css.
* Make return section a bit less verbose.
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Freq events may not always be affine to a particular CPU. As such,
account_event_cpu() may crash if we account per cpu a freq event
that has event->cpu == -1.
To solve this, lets account freq events globally. In practice
this doesn't change much the picture because perf tools create
per-task perf events with one event per CPU by default. Profiling a
single CPU is usually a corner case so there is no much point in
optimizing things that way.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1375460996-16329-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we fail to allocate the callchain buffers, we roll back the refcount
we did and return from get_callchain_buffers().
However we take the refcount and allocate under the callchain lock
but the rollback is done outside the lock.
As a result, while we roll back, some concurrent callchain user may
call get_callchain_buffers(), see the non-zero refcount and give up
because the buffers are NULL without itself retrying the allocation.
The consequences aren't that bad but that behaviour looks weird enough and
it's better to give their chances to the following callchain users where
we failed.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1375460996-16329-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
cgroup->subsys[] will become RCU protected and thus all cgroup_css()
usages should either be under RCU read lock or cgroup_mutex. This
patch updates cgroup_css_from_dir() which returns the matching
cgroup_subsys_state given a directory file and subsys_id so that it
requires RCU read lock and updates its sole user
perf_cgroup_connect().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
cgroup is in the process of converting to css (cgroup_subsys_state)
from cgroup as the principal subsystem interface handle. This is
mostly to prepare for the unified hierarchy support where css's will
be created and destroyed dynamically but also helps cleaning up
subsystem implementations as css is usually what they are interested
in anyway.
cgroup_taskset which is used by the subsystem attach methods is the
last cgroup subsystem API which isn't using css as the handle. Update
cgroup_taskset_cur_cgroup() to cgroup_taskset_cur_css() and
cgroup_taskset_for_each() to take @skip_css instead of @skip_cgrp.
The conversions are pretty mechanical. One exception is
cpuset::cgroup_cs(), which lost its last user and got removed.
This patch shouldn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup *
in subsystem implementations for the following reasons.
* With unified hierarchy, subsystems will be dynamically bound and
unbound from cgroups and thus css's (cgroup_subsys_state) may be
created and destroyed dynamically over the lifetime of a cgroup,
which is different from the current state where all css's are
allocated and destroyed together with the associated cgroup. This
in turn means that cgroup_css() should be synchronized and may
return NULL, making it more cumbersome to use.
* Differing levels of per-subsystem granularity in the unified
hierarchy means that the task and descendant iterators should behave
differently depending on the specific subsystem the iteration is
being performed for.
* In majority of the cases, subsystems only care about its part in the
cgroup hierarchy - ie. the hierarchy of css's. Subsystem methods
often obtain the matching css pointer from the cgroup and don't
bother with the cgroup pointer itself. Passing around css fits
much better.
This patch converts all cgroup_subsys methods to take @css instead of
@cgroup. The conversions are mostly straight-forward. A few
noteworthy changes are
* ->css_alloc() now takes css of the parent cgroup rather than the
pointer to the new cgroup as the css for the new cgroup doesn't
exist yet. Knowing the parent css is enough for all the existing
subsystems.
* In kernel/cgroup.c::offline_css(), unnecessary open coded css
dereference is replaced with local variable access.
This patch shouldn't cause any behavior differences.
v2: Unnecessary explicit cgrp->subsys[] deref in css_online() replaced
with local variable @css as suggested by Li Zefan.
Rebased on top of new for-3.12 which includes for-3.11-fixes so
that ->css_free() invocation added by da0a12caff ("cgroup: fix a
leak when percpu_ref_init() fails") is converted too. Suggested
by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
The names of the two struct cgroup_subsys_state accessors -
cgroup_subsys_state() and task_subsys_state() - are somewhat awkward.
The former clashes with the type name and the latter doesn't even
indicate it's somehow related to cgroup.
We're about to revamp large portion of cgroup API, so, let's rename
them so that they're less awkward. Most per-controller usages of the
accessors are localized in accessor wrappers and given the amount of
scheduled changes, this isn't gonna add any noticeable headache.
Rename cgroup_subsys_state() to cgroup_css() and task_subsys_state()
to task_css(). This patch is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
It's possible some of the counters in the group could be
disabled when sampling member of the event group is reading
the rest via PERF_SAMPLE_READ sample type processing. Disabled
counters could then produce wrong numbers.
Fixing that by reading only enabled counters for PERF_SAMPLE_READ
sample type processing.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-wwkjb0bbcuslnz0klrmqi26r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The only way to get the event ID is by reading the event fd,
followed by parsing the ID value out of the returned data.
While this is ok for current read format used by perf tool,
it is not ok when we use PERF_FORMAT_GROUP format.
With this format the data are returned for the whole group
and there's no way to find out what ID belongs to our fd
(if we are not group leader event).
Adding a simple ioctl that returns event primary ID for given fd.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-v1bn5cto707jn0bon34afqr1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently the full dynticks subsystem keep the
tick alive as long as there are perf events running.
This prevents the tick from being stopped as long as features
such that the lockup detectors are running. As a temporary fix,
the lockup detector is disabled by default when full dynticks
is built but this is not a long term viable solution.
To fix this, only keep the tick alive when an event configured
with a frequency rather than a period is running on the CPU,
or when an event throttles on the CPU.
These are the only purposes of the perf tick, especially now that
the rotation of flexible events is handled from a seperate hrtimer.
The tick can be shutdown the rest of the time.
Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-8-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is going to be used by the full dynticks subsystem
as a finer-grained information to know when to keep and
when to stop the tick.
Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-7-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When an event is migrated, move the event per-cpu
accounting accordingly so that branch stack and cgroup
events work correctly on the new CPU.
Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-6-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This way we can use the per-cpu handling seperately.
This is going to be used by to fix the event migration
code accounting.
Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Gather all the event accounting code to a single place,
once all the prerequisites are completed. This simplifies
the refcounting.
Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In case of allocation failure, get_callchain_buffer() keeps the
refcount incremented for the current event.
As a result, when get_callchain_buffers() returns an error,
we must cleanup what it did by cancelling its last refcount
with a call to put_callchain_buffers().
This is a hack in order to be able to call free_event()
after that failure.
The original purpose of that was to simplify the failure
path. But this error handling is actually counter intuitive,
ugly and not very easy to follow because one expect to
see the resources used to perform a service to be cleaned
by the callee if case of failure, not by the caller.
So lets clean this up by cancelling the refcount from
get_callchain_buffer() in case of failure. And correctly free
the event accordingly in perf_event_alloc().
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On callchain buffers allocation failure, free_event() is
called and all the accounting performed in perf_event_alloc()
for that event is cancelled.
But if the event has branch stack sampling, it is unaccounted
as well from the branch stack sampling events refcounts.
This is a bug because this accounting is performed after the
callchain buffer allocation. As a result, the branch stack sampling
events refcount can become negative.
To fix this, move the branch stack event accounting before the
callchain buffer allocation.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Due to a discussion with Adrian I had a good look at the perf_event_type record
layout and found the documentation to be somewhat unclear.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130716150907.GL23818@dyad.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Here are some driver core patches for 3.11-rc2. They aren't really
bugfixes, but a bunch of new helper macros for drivers to properly
create attribute groups, which drivers and subsystems need to fix up a
ton of race issues with incorrectly creating sysfs files (binary and
normal) after userspace has been told that the device is present.
Also here is the ability to create binary files as attribute groups, to
solve that race condition, which was impossible to do before this, so
that's my fault the drivers were broken.
The majority of the .c changes is indenting and moving code around a
bit. It affects no existing code, but allows the large backlog of 70+
patches that I already have created to start flowing into the different
subtrees, instead of having to live in my driver-core tree, causing
merge nightmares in linux-next for the next few months.
These were finalized too late for the -rc1 merge window, which is why
they were didn't make that pull request, testing and review from others
didn't happen until a few weeks ago, and then there's the whole
distraction of the past few days, which prevented these from getting to
you sooner, sorry about that.
Oh, and there's a bugfix for the documentation build warning in here as
well. All of these have been in linux-next this week, with no reported
problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg KH:
"Here are some driver core patches for 3.11-rc2. They aren't really
bugfixes, but a bunch of new helper macros for drivers to properly
create attribute groups, which drivers and subsystems need to fix up a
ton of race issues with incorrectly creating sysfs files (binary and
normal) after userspace has been told that the device is present.
Also here is the ability to create binary files as attribute groups,
to solve that race condition, which was impossible to do before this,
so that's my fault the drivers were broken.
The majority of the .c changes is indenting and moving code around a
bit. It affects no existing code, but allows the large backlog of 70+
patches that I already have created to start flowing into the
different subtrees, instead of having to live in my driver-core tree,
causing merge nightmares in linux-next for the next few months.
These were finalized too late for the -rc1 merge window, which is why
they were didn't make that pull request, testing and review from
others didn't happen until a few weeks ago, and then there's the whole
distraction of the past few days, which prevented these from getting
to you sooner, sorry about that.
Oh, and there's a bugfix for the documentation build warning in here
as well. All of these have been in linux-next this week, with no
reported problems"
* tag 'driver-core-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
driver-core: fix new kernel-doc warning in base/platform.c
sysfs: use file mode defines from stat.h
sysfs: add more helper macro's for (bin_)attribute(_groups)
driver core: add default groups to struct class
driver core: Introduce device_create_groups
sysfs: prevent warning when only using binary attributes
sysfs: add support for binary attributes in groups
driver core: device.h: add RW and RO attribute macros
sysfs.h: add BIN_ATTR macro
sysfs.h: add ATTRIBUTE_GROUPS() macro
sysfs.h: add __ATTR_RW() macro
A number of parts of the kernel created their own version of this, might
as well have the sysfs core provide it instead.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.
[1] https://lkml.org/lkml/2013/5/20/589
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
It gives the following benefits:
- only one function pointer is passed along the way
- the 'match' function is called within output function
and could be inlined by the compiler
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373388991-9711-1-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jiri managed to trigger this warning:
[] ======================================================
[] [ INFO: possible circular locking dependency detected ]
[] 3.10.0+ #228 Tainted: G W
[] -------------------------------------------------------
[] p/6613 is trying to acquire lock:
[] (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
[]
[] but task is already holding lock:
[] (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
[]
[] which lock already depends on the new lock.
[]
[] the existing dependency chain (in reverse order) is:
[]
[] -> #4 (&ctx->lock){-.-...}:
[] -> #3 (&rq->lock){-.-.-.}:
[] -> #2 (&p->pi_lock){-.-.-.}:
[] -> #1 (&rnp->nocb_gp_wq[1]){......}:
[] -> #0 (rcu_node_0){..-...}:
Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.
Therefore solve it by making the entire RCU read side non-preemptible.
Also pull out the retry from under the non-preempt to play nice with RT.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Helped-out-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently when the child context for inherited events is
created, it's based on the pmu object of the first event
of the parent context.
This is wrong for the following scenario:
- HW context having HW and SW event
- HW event got removed (closed)
- SW event stays in HW context as the only event
and its pmu is used to clone the child context
The issue starts when the cpu context object is touched
based on the pmu context object (__get_cpu_context). In
this case the HW context will work with SW cpu context
ending up with following WARN below.
Fixing this by using parent context pmu object to clone
from child context.
Addresses the following warning reported by Vince Weaver:
[ 2716.472065] ------------[ cut here ]------------
[ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x)
[ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn
[ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2
[ 2716.476035] Hardware name: AOpen DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2
[ 2716.476035] 0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18
[ 2716.476035] ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad
[ 2716.476035] ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550
[ 2716.476035] Call Trace:
[ 2716.476035] [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70
[ 2716.476035] [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f
[ 2716.476035] [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194
[ 2716.476035] [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c
[ 2716.476035] [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394
[ 2716.476035] [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98
[ 2716.476035] [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad
[ 2716.476035] [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1
[ 2716.476035] [<ffffffff8100205d>] ? do_signal+0x3c/0x432
[ 2716.476035] [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141
[ 2716.476035] [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90
[ 2716.476035] [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118
[ 2716.476035] [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c
[ 2716.476035] [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6
[ 2716.476035] [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d
[ 2716.476035] [<ffffffff813654f5>] ? retint_signal+0x3d/0x78
[ 2716.476035] ---[ end trace 827178d8a5966c3d ]---
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch fixes a serious bug in:
14c63f17b1 perf: Drop sample rate when sampling is too slow
There was an misunderstanding on the API of the do_div()
macro. It returns the remainder of the division and this
was not what the function expected leading to disabling the
interrupt latency watchdog.
This patch also remove a duplicate assignment in
perf_sample_event_took().
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: dave.hansen@linux.intel.com
Cc: ak@linux.intel.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second. If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.
This way, we don't have a runaway sampling process eating up the
CPU.
This patch can tend to drop the sample rate down to level where
perf doesn't work very well. *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.
I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.
BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
[ Prettified it a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch simply moves all per-cpu variables into the new
single per-cpu "struct bp_cpuinfo".
To me this looks more logical and clean, but this can also
simplify the further potential changes. In particular, I do not
think this memory should be per-cpu, it is never used "locally".
After this change it is trivial to turn it into, say,
bootmem[nr_cpu_ids].
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155020.GA6350@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. register_wide_hw_breakpoint() can use unregister_ if failure,
no need to duplicate the code.
2. "struct perf_event **pevent" adds the unnecesary lever of
indirection and complication, use per_cpu(*cpu_events, cpu).
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155018.GA6347@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add the trivial helper which simply returns cpumask_of() or
cpu_possible_mask depending on bp->cpu.
Change fetch_bp_busy_slots() and toggle_bp_slot() to always do
for_each_cpu(cpumask_of_bp) to simplify the code and avoid the
code duplication.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155015.GA6340@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Change toggle_bp_slot() to make "weight" negative if !enable.
This way we can always use "+ weight" without additional "if
(enable)" check and toggle_bp_task_slot() no longer needs this
arg.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155013.GA6337@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The enable/disable logic in toggle_bp_slot() is not symmetrical
and imho very confusing. "old_count" in toggle_bp_task_slot() is
actually new_count because this bp was already removed from the
list.
Change toggle_bp_slot() to always call list_add/list_del after
toggle_bp_task_slot(). This way old_idx is task_bp_pinned() and
this entry should be decremented, new_idx is +/-weight and we
need to increment this element. The code/logic looks obvious.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155011.GA6330@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
trinity fuzzer triggered WARN_ONCE("Can't find any breakpoint
slot") in arch_install_hw_breakpoint() but the problem is not
arch-specific.
The problem is, task_bp_pinned(cpu) checks "cpu == iter->cpu"
but this doesn't account the "all cpus" events with iter->cpu <
0.
This means that, say, register_user_hw_breakpoint(tsk) can
happily create the arbitrary number > HBP_NUM of breakpoints
which can not be activated. toggle_bp_task_slot() is equally
wrong by the same reason and nr_task_bp_pinned[] can have
negative entries.
Simple test:
# perl -e 'sleep 1 while 1' &
# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10,mem:0x10 -p `pidof perl`
Before this patch this triggers the same problem/WARN_ON(),
after the patch it correctly fails with -ENOSPC.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Peter Zijlstra