alistair23-linux/kernel
Dmitry Adamushko ce96b5ac74 sched: fix __set_task_cpu() SMP race
Grant Wilson has reported rare SCHED_FAIR_USER crashes on his quad-core
system, which crashes can only be explained via runqueue corruption.

there is a narrow SMP race in __set_task_cpu(): after ->cpu is set up to
a new value, task_rq_lock(p, ...) can be successfuly executed on another
CPU. We must ensure that updates of per-task data have been completed by
this moment.

this bug has been hiding in the Linux scheduler for an eternity (we never
had any explicit barrier for task->cpu in set_task_cpu() - so the bug was
introduced in 2.5.1), but only became visible via set_task_cfs_rq() being
accidentally put after the task->cpu update. It also probably needs a
sufficiently out-of-order CPU to trigger.

Reported-by: Grant Wilson <grant.wilson@zen.co.uk>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-11-15 20:57:40 +01:00
..
irq __do_IRQ does not check IRQ_DISABLED when IRQ_PER_CPU is set 2007-11-14 18:45:43 -08:00
power hibernate: fix lockdep report 2007-11-14 18:45:43 -08:00
time time: fix inconsistent function names in comments 2007-11-05 15:12:33 -08:00
.gitignore
acct.c whitespace fixes: process accounting 2007-10-18 14:37:24 -07:00
audit.c [PATCH] audit: watching subtrees 2007-10-21 02:37:45 -04:00
audit.h [PATCH] audit: watching subtrees 2007-10-21 02:37:45 -04:00
audit_tree.c [PATCH] audit: watching subtrees 2007-10-21 02:37:45 -04:00
auditfilter.c [PATCH] audit: watching subtrees 2007-10-21 02:37:45 -04:00
auditsc.c auditsc: fix kernel-doc param warnings 2007-10-22 19:40:02 -07:00
capability.c Uninline find_pid etc set of functions 2007-10-19 11:53:41 -07:00
cgroup.c Improve cgroup printks 2007-11-14 18:45:37 -08:00
cgroup_debug.c Task Control Groups: simple task cgroup debug info subsystem 2007-10-19 11:53:36 -07:00
compat.c Merge ssh://master.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt 2007-10-18 15:12:41 -07:00
configs.c
cpu.c CPU HOTPLUG: avoid hotadd when proper possible_map isn't specified 2007-10-19 11:53:44 -07:00
cpuset.c hotplug cpu: migrate a task within its cpuset 2007-10-19 11:53:44 -07:00
delayacct.c Add scaled time to taskstats based process accounting 2007-10-18 14:37:28 -07:00
dma.c whitespace fixes: DMA channel allocator 2007-10-18 14:37:24 -07:00
exec_domain.c whitespace fixes: execution domains 2007-10-18 14:37:26 -07:00
exit.c Uninline fork.c/exit.c 2007-10-19 11:53:56 -07:00
extable.c
fork.c sched: fix copy_namespace() <-> sched_fork() dependency in do_fork 2007-11-09 22:39:39 +01:00
futex.c kernel/futex.c: make 3 functions static 2007-11-05 21:53:46 +11:00
futex_compat.c [FUTEX] Fix address computation in compat code. 2007-11-09 16:13:08 -08:00
hrtimer.c Quieten hrtimer printk: "Switched to high resolution mode .." 2007-10-29 09:39:38 +01:00
itimer.c whitespace fixes: interval timers 2007-10-18 14:37:26 -07:00
kallsyms.c
Kconfig.hz
Kconfig.instrumentation Linux Kernel Markers 2007-10-19 11:53:54 -07:00
Kconfig.preempt Move PREEMPT_NOTIFIERS into an always-included Kconfig 2007-10-17 08:42:55 -07:00
kexec.c Extended crashkernel command line 2007-10-19 11:53:49 -07:00
kfifo.c
kmod.c
kprobes.c kprobes: support kretprobe blacklist 2007-10-16 09:43:10 -07:00
ksysfs.c add-vmcore: cleanup the coding style according to Andrew's comments 2007-10-17 08:42:54 -07:00
kthread.c
latency.c
lockdep.c lockdep: fix a typo in the __lock_acquire comment 2007-10-28 20:47:01 +01:00
lockdep_internals.h
lockdep_proc.c
Makefile revert "Task Control Groups: example CPU accounting subsystem" 2007-11-14 18:45:40 -08:00
marker.c Linux Kernel Markers: fix marker mutex not taken upon module load 2007-11-14 18:45:40 -08:00
module.c Linux Kernel Markers 2007-10-19 11:53:54 -07:00
mutex-debug.c
mutex-debug.h
mutex.c lockdep: fixup mutex annotations 2007-10-11 22:11:12 +02:00
mutex.h
notifier.c Add kernel/notifier.c 2007-10-19 11:53:34 -07:00
ns_cgroup.c cgroups: implement namespace tracking subsystem 2007-10-19 11:53:37 -07:00
nsproxy.c pid namespaces: allow cloning of new namespace 2007-10-19 11:53:39 -07:00
panic.c trivial comment wording/typo fix regarding taint flags 2007-10-20 00:30:06 +02:00
params.c fix param_sysfs_builtin name length check 2007-11-14 18:45:42 -08:00
pid.c pidns: Place under CONFIG_EXPERIMENTAL 2007-11-14 18:45:43 -08:00
posix-cpu-timers.c Isolate some explicit usage of task->tgid 2007-10-19 11:53:40 -07:00
posix-timers.c Isolate some explicit usage of task->tgid 2007-10-19 11:53:40 -07:00
printk.c serial: turn serial console suspend a boot rather than compile time option 2007-10-18 14:37:19 -07:00
profile.c sched: document profile=sleep requiring CONFIG_SCHEDSTATS 2007-10-24 18:23:50 +02:00
ptrace.c Isolate some explicit usage of task->tgid 2007-10-19 11:53:40 -07:00
rcupdate.c Clean up duplicate includes in kernel/ 2007-10-17 08:42:48 -07:00
rcutorture.c Make rcutorture RNG use temporal entropy 2007-10-17 08:42:53 -07:00
relay.c whitespace fixes: relayfs 2007-10-18 14:37:24 -07:00
resource.c Add IORESOUCE_BUSY flag for System RAM 2007-11-14 18:45:39 -08:00
rtmutex-debug.c Use helpers to obtain task pid in printks 2007-10-19 11:53:43 -07:00
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c Use helpers to obtain task pid in printks 2007-10-19 11:53:43 -07:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c sched: fix __set_task_cpu() SMP race 2007-11-15 20:57:40 +01:00
sched_debug.c sched: reintroduce the sched_min_granularity tunable 2007-11-09 22:39:37 +01:00
sched_fair.c sched: fix copy_namespace() <-> sched_fork() dependency in do_fork 2007-11-09 22:39:39 +01:00
sched_idletask.c sched: isolate SMP balancing code a bit more 2007-10-24 18:23:51 +02:00
sched_rt.c sched: isolate SMP balancing code a bit more 2007-10-24 18:23:51 +02:00
sched_stats.h sched: fix delay accounting regression 2007-11-09 22:39:37 +01:00
seccomp.c
signal.c sigwait eats blocked default-ignore signals 2007-11-12 16:05:23 -08:00
softirq.c
softlockup.c Use helpers to obtain task pid in printks 2007-10-19 11:53:43 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys.c Isolate the explicit usage of signal->pgrp 2007-10-19 11:53:43 -07:00
sys_ni.c [COMPAT]: Fix build on COMPAT platforms when CONFIG_NET is disabled. 2007-10-30 21:29:56 -07:00
sysctl.c sysctl: check length at deprecated_sysctl_warning 2007-11-14 18:45:37 -08:00
sysctl_check.c [SYSCTL]: Fix warning for token-ring from sysctl checker 2007-11-13 21:15:24 -08:00
taskstats.c kernel/taskstats.c: fix bogus nlmsg_free() 2007-11-14 18:45:44 -08:00
time.c whitespace fixes: time syscalls 2007-10-18 14:37:24 -07:00
timer.c sched: restore deterministic CPU accounting on powerpc 2007-11-09 22:39:38 +01:00
tsacct.c Add scaled time to taskstats based process accounting 2007-10-18 14:37:28 -07:00
uid16.c
user.c sched: make cpu_shares_{show,store}() static 2007-10-24 18:23:50 +02:00
user_namespace.c
utsname.c
utsname_sysctl.c
wait.c
workqueue.c Use helpers to obtain task pid in printks 2007-10-19 11:53:43 -07:00