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.

Reviewed-by: David Ahern <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Neil Horman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 5 insertions, 2 deletions

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index c5748c52318f..e389815078d3 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;