From c88f2096136416b261bd3647cc260935f6e95805 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 8 Sep 2014 16:31:07 +0200 Subject: [PATCH] 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 Signed-off-by: Jiri Olsa Acked-by: Stephane Eranian Acked-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Namhyung Kim Cc: Paul Mackerras Cc: Stephane Eranian Cc: David Ahern Link: http://lkml.kernel.org/r/20140908143107.GG17728@krava.brq.redhat.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index f917dec6f897..733c61636f0d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -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)