perf: Fix NULL deref in inheritance code

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Liming found a NULL deref when a task has a perf context but no
counters  when it forks.

This can occur in two cases, a race during construction where
the fork hits after installing the context but before the first
counter gets inserted, or more reproducably, a fork after the
last counter is closed (which leaves the context around).

Reported-by: Wang Liming <liming.wang@windriver.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
CC: <stable@kernel.org>
LKML-Reference: <1262185684.7135.222.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

...

This commit is contained in:

Peter Zijlstra 2009-12-30 16:00:35 +01:00 • committed by Ingo Molnar

parent 48b5ba9cc9

commit 05cbaa2853

1 changed files with 2 additions and 3 deletions

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kernel/perf_event.c

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