perf: Fix reading in perf_event_read()
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Wed, 26 Jan 2011 14:38:35 +0000 (15:38 +0100)
committerIngo Molnar <mingo@elte.hu>
Thu, 3 Feb 2011 11:15:46 +0000 (12:15 +0100)
commit542e72fc90f5ed9eecb574f80f70868c7f296093
treeb42abb2d44ed771759eee63ce00378df02d689ca
parent9ffdc6c37df131f89d52001e0ef03091b158826f
perf: Fix reading in perf_event_read()

It is quite possible for the event to have been disabled between
perf_event_read() sending the IPI and the CPU servicing the IPI and
calling __perf_event_read(), hence revalidate the state.

Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/perf_event.c