Commit c88f2096 authored Sep 08, 2014 by Jiri Olsa Committed by Ingo Molnar Sep 16, 2014

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>

parent a08b6769

kernel/events/core.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -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)

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