From: Stephane Eranian <eranian@xxxxxxxxxx> In case the sampling buffer has no "payload" pages, nr_pages is 0. The problem is that the error path in perf_output_begin() skips to a label which assumes perf_output_lock() has been issued which is not the case. That triggers a WARN_ON() in perf_output_unlock(). This patch fixes the problem by skipping perf_output_unlock() in case data->nr_pages is 0. Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Mike Galbraith <efault@xxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> LKML-Reference: <4bf13674.014fd80a.6c82.ffffb20c@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> Upstream-commit: 00d1d0b095ba4e5c0958cb228b2a9c445d4a339d Signed-off-by: John Kacur <jkacur@xxxxxxxxxx> --- kernel/perf_event.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 43c1dfb..e353be2 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2933,7 +2933,7 @@ int perf_output_begin(struct perf_output_handle *handle, handle->sample = sample; if (!data->nr_pages) - goto fail; + goto out; have_lost = atomic_read(&data->lost); if (have_lost) -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
