diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2016-02-24 18:45:46 +0100 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-04-13 12:32:13 +0200 |
| commit | e76d24496070cd36c2452959785be42e2f7a99a2 (patch) | |
| tree | 7f89eb4bae222eadccb499cee07bb720eb7c8a20 /kernel/itimer.c | |
| parent | 0690955eef2536b10c94a403775f6b014ca51273 (diff) | |
perf: Cure event->pending_disable race
commit 28a967c3a2f99fa3b5f762f25cb2a319d933571b upstream.
Because event_sched_out() checks event->pending_disable _before_
actually disabling the event, it can happen that the event fires after
it checks but before it gets disabled.
This would leave event->pending_disable set and the queued irq_work
will try and process it.
However, if the event trigger was during schedule(), the event might
have been de-scheduled by the time the irq_work runs, and
perf_event_disable_local() will fail.
Fix this by checking event->pending_disable _after_ we call
event->pmu->del(). This depends on the latter being a compiler
barrier, such that the compiler does not lift the load and re-creates
the problem.
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160224174948.040469884@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: mydongistiny <jaysonedson@gmail.com>
Diffstat (limited to 'kernel/itimer.c')
0 files changed, 0 insertions, 0 deletions