Em Mon, Jun 07, 2021 at 05:31:01PM +0200, Peter Zijlstra escreveu:

On Wed, Jun 02, 2021 at 06:30:06PM +0800, Leo Yan wrote:

quoted

Use WRITE_ONCE() for updating aux_tail, so can avoid unexpected memory
behaviour.

Signed-off-by: Leo Yan <redacted>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Leo, this one is dependendant on the 6/8, will wait for a resubmission,
keeping 5/8 tho, as was Acked and applies cleanly, perf/core.
 

quoted

---
 tools/perf/util/auxtrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index e625bc76cdde..abc4282f5272 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h

@@ -458,7 +458,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
 
 	/* Ensure all reads are done before we write the tail out */
 	smp_mb();
-	pc->aux_tail = tail;
+	WRITE_ONCE(pc->aux_tail, tail);
 }
 
 int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,

-- 
2.25.1

-- 

- Arnaldo