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Date: Mon, 17 May 2010 12:46:01 +0200 From: Stephane Eranian <eranian@...gle.com> To: linux-kernel@...r.kernel.org Cc: peterz@...radead.org, mingo@...e.hu, paulus@...ba.org, davem@...emloft.net, fweisbec@...il.com, acme@...radead.org, perfmon2-devel@...ts.sf.net, eranian@...il.com, eranian@...gle.com Subject: [PATCH] perf_events: fix errors path in perf_output_begin() 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() is perf_output_unlock(). This patch fixes the problem by adding a new label and skipping perf_task_unlock() in case data->nr_pages is 0. Signed-off-by: Stephane Eranian <eranian@...gle.com> -- diff --git a/kernel/perf_event.c b/kernel/perf_event.c index a4fa381..95137b6 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3035,8 +3035,10 @@ int perf_output_begin(struct perf_output_handle *handle, handle->nmi = nmi; handle->sample = sample; - if (!data->nr_pages) - goto fail; + if (!data->nr_pages) { + atomic_inc(&data->lost); + goto out; + } have_lost = atomic_read(&data->lost); if (have_lost) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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