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perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 

Revert PERF_EVENT_STATE_EXIT check on read syscall path.
It breaks standard way to read counter, which is to open
the counter, wait for the monitored process to die and
read the counter.

Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/20140908143107.GG17728@krava.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Jiri Olsa 2014-09-08 16:31:07 +02:00 committed by Ingo Molnar
parent a08b6769d4
commit c88f209613
1 changed files with 1 additions and 2 deletions
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3
kernel/events/core.c
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@ -3601,8 +3601,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
* error state (i.e. because it was pinned but it couldn't be
* scheduled on to the CPU at some point).
*/
if ((event->state == PERF_EVENT_STATE_ERROR) ||
(event->state == PERF_EVENT_STATE_EXIT))
if (event->state == PERF_EVENT_STATE_ERROR)
return 0;
if (count < event->read_size)