[PATCH] perf_events: fix ordering bug in perf_output_sample()

From: Stephane Eranian <eranian@google.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@elte.hu, paulus@samba.org,
	davem@davemloft.net, fweisbec@gmail.com, robert.richter@amd.com,
	perfmon2-devel@lists.sf.net, eranian@gmail.com,
	eranian@google.com
Subject: [PATCH] perf_events: fix ordering bug in perf_output_sample()
Date: Thu, 18 Mar 2010 14:42:01 +0200	[thread overview]
Message-ID: <4ba2317a.8109cc0a.2858.ffffcd0c@mx.google.com> (raw)

	In order to parse a sample correctly based on the information
	requested via sample_type, the kernel needs to save each component
	in a known order. There is no type value saved with each component.
	The current convention is that each component is saved according to
	the order in enum perf_event_sample_format. But perf_output_sample()
	was not completely following this convention, thereby making samples
	impossible to parse without internal kernel knowledge.

	This patch puts things in the right order.

	Signed-off-by: Stephane Eranian <eranian@google.com>

--
 perf_event.c |   24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 455393e..b35df1d 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3167,18 +3167,6 @@ void perf_output_sample(struct perf_output_handle *handle,
 	if (sample_type & PERF_SAMPLE_ADDR)
 		perf_output_put(handle, data->addr);
 
-	if (sample_type & PERF_SAMPLE_ID)
-		perf_output_put(handle, data->id);
-
-	if (sample_type & PERF_SAMPLE_STREAM_ID)
-		perf_output_put(handle, data->stream_id);
-
-	if (sample_type & PERF_SAMPLE_CPU)
-		perf_output_put(handle, data->cpu_entry);
-
-	if (sample_type & PERF_SAMPLE_PERIOD)
-		perf_output_put(handle, data->period);
-
 	if (sample_type & PERF_SAMPLE_READ)
 		perf_output_read(handle, event);
 
@@ -3198,6 +3186,18 @@ void perf_output_sample(struct perf_output_handle *handle,
 		}
 	}
 
+	if (sample_type & PERF_SAMPLE_ID)
+		perf_output_put(handle, data->id);
+
+	if (sample_type & PERF_SAMPLE_CPU)
+		perf_output_put(handle, data->cpu_entry);
+
+	if (sample_type & PERF_SAMPLE_STREAM_ID)
+		perf_output_put(handle, data->stream_id);
+
+	if (sample_type & PERF_SAMPLE_PERIOD)
+		perf_output_put(handle, data->period);
+
 	if (sample_type & PERF_SAMPLE_RAW) {
 		if (data->raw) {
 			perf_output_put(handle, data->raw->size);
