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authorFrederic Weisbecker <fweisbec@gmail.com>2013-07-23 02:30:59 +0200
committerIngo Molnar <mingo@kernel.org>2013-07-30 22:22:58 +0200
commit6050cb0b0b366092d1383bc23d7b16cd26db00f0 (patch)
treee29edecc20a04e17aa4c7f83d21a140d3e377356 /kernel/events
parent7d9ffa8961482232d964173cccba6e14d2d543b2 (diff)
perf: Fix branch stack refcount leak on callchain init failure
On callchain buffers allocation failure, free_event() is called and all the accounting performed in perf_event_alloc() for that event is cancelled. But if the event has branch stack sampling, it is unaccounted as well from the branch stack sampling events refcounts. This is a bug because this accounting is performed after the callchain buffer allocation. As a result, the branch stack sampling events refcount can become negative. To fix this, move the branch stack event accounting before the callchain buffer allocation. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1374539466-4799-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 127411400116..f35aa7e69e2d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6567,6 +6567,12 @@ done:
atomic_inc(&nr_comm_events);
if (event->attr.task)
atomic_inc(&nr_task_events);
+ if (has_branch_stack(event)) {
+ static_key_slow_inc(&perf_sched_events.key);
+ if (!(event->attach_state & PERF_ATTACH_TASK))
+ atomic_inc(&per_cpu(perf_branch_stack_events,
+ event->cpu));
+ }
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
err = get_callchain_buffers();
if (err) {
@@ -6574,12 +6580,6 @@ done:
return ERR_PTR(err);
}
}
- if (has_branch_stack(event)) {
- static_key_slow_inc(&perf_sched_events.key);
- if (!(event->attach_state & PERF_ATTACH_TASK))
- atomic_inc(&per_cpu(perf_branch_stack_events,
- event->cpu));
- }
}
return event;