| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 007/165] perf: overflow/perf_count_sw_cpu_clock crashes recent kernels | Date | Wed, 15 Aug 2012 15:45:51 -0400 |
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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
The below patch is for -stable only, upstream has a much larger patch that contains the below hunk in commit a8b0ca17b80e92faab46ee7179ba9e99ccb61233
Vince found that under certain circumstances software event overflows go wrong and deadlock. Avoid trying to delete a timer from the timer callback.
Reported-by: Vince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> [PG: backport from 2.6.32 queue, see https://lkml.org/lkml/2011/8/3/125 ] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- kernel/perf_event.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index b203546..540c26b 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3907,12 +3907,8 @@ static int __perf_event_overflow(struct perf_event *event, int nmi, if (events && atomic_dec_and_test(&event->event_limit)) { ret = 1; event->pending_kill = POLL_HUP; - if (nmi) { - event->pending_disable = 1; - perf_pending_queue(&event->pending, - perf_pending_event); - } else - perf_event_disable(event); + event->pending_disable = 1; + perf_pending_queue(&event->pending, perf_pending_event); } if (event->overflow_handler) -- 1.7.12.rc2
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