linux-kernel - [PATCHv3 1/2] perf tools: Fix raw sample reading

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Date:	Thu, 29 Sep 2011 17:05:08 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	acme@...hat.com, a.p.zijlstra@...llo.nl, mingo@...e.hu,
	paulus@...ba.org
Cc:	linux-kernel@...r.kernel.org, rostedt@...dmis.org,
	nhorman@...driver.com, eric.dumazet@...il.com,
	David Ahern <dsahern@...il.com>, Jiri Olsa <jolsa@...hat.com>
Subject: [PATCHv3 1/2] perf tools: Fix raw sample reading

Wrong pointer is being passed for raw data sanity checking,
when parsing sample event.

This ends up with invalid event and perf record being stuck in
__perf_session__process_events function during processing
build IDs (process_buildids function).

Following command hangs up in my setup:
	./perf record -e raw_syscalls:sys_enter ls

The fix is to use proper pointer to the raw data instead
of the 'u' union.

CC: David Ahern <dsahern@...il.com>
Signed-off-by: Jiri Olsa <jolsa@...hat.com>
---
 tools/perf/util/evsel.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index c5748c5..e389815 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -449,6 +449,8 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
 	}
 
 	if (type & PERF_SAMPLE_RAW) {
+		const u64 *pdata;
+
 		u.val64 = *array;
 		if (WARN_ONCE(swapped,
 			      "Endianness of raw data not corrected!\n")) {
@@ -462,11 +464,12 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
 			return -EFAULT;
 
 		data->raw_size = u.val32[0];
+		pdata = (void *) array + sizeof(u32);
 
-		if (sample_overlap(event, &u.val32[1], data->raw_size))
+		if (sample_overlap(event, pdata, data->raw_size))
 			return -EFAULT;
 
-		data->raw_data = &u.val32[1];
+		data->raw_data = (void *) pdata;
 	}
 
 	return 0;
-- 
1.7.4

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