Messages in this thread Patch in this message | | | Date | Fri, 05 Aug 2011 17:02:24 -0700 | From | Greg KH <> | Subject | [54/55] perf: overflow/perf_count_sw_cpu_clock crashes recent kernels |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
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>
--- kernel/perf_event.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
--- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3694,12 +3694,8 @@ static int __perf_event_overflow(struct 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); } perf_event_output(event, nmi, data, regs);
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