From 68183a00aebc8b7b89975578cda38358bf6f93a1 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 16 Sep 2011 09:13:29 -0400
Subject: [PATCH] perf: Fix software event overflow
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>
---
kernel/perf_event.c | 8 ++------
1 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index fa8123e..720b764 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3985,12 +3985,8 @@ 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)
--
1.7.6