perf: Allow perf_release() with !event->ctx
In the err_file: fput(event_file) case, the event will not yet have been attached to a context. However perf_release() does assume it has been. Cure this. Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dvyukov@google.com Cc: eranian@google.com Cc: oleg@redhat.com Cc: panand@redhat.com Cc: sasha.levin@oracle.com Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160224174947.793996260@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -3754,9 +3754,19 @@ static void put_event(struct perf_event *event)
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*/
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int perf_event_release_kernel(struct perf_event *event)
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{
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struct perf_event_context *ctx;
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struct perf_event_context *ctx = event->ctx;
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struct perf_event *child, *tmp;
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/*
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* If we got here through err_file: fput(event_file); we will not have
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* attached to a context yet.
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*/
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if (!ctx) {
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WARN_ON_ONCE(event->attach_state &
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(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
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goto no_ctx;
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}
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if (!is_kernel_event(event))
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perf_remove_from_owner(event);
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@ -3832,8 +3842,8 @@ again:
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}
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mutex_unlock(&event->child_mutex);
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/* Must be the last reference */
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put_event(event);
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no_ctx:
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put_event(event); /* Must be the 'last' reference */
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return 0;
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}
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EXPORT_SYMBOL_GPL(perf_event_release_kernel);
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