Re: [PATCH v2 7/8] perf auxtrace: Use WRITE_ONCE() for updating aux_tail

[Adrian Hunter]

On 2/06/21 1:30 pm, Leo Yan wrote:
> Use WRITE_ONCE() for updating aux_tail, so can avoid unexpected memory
> behaviour.
> 
> Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
>  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,
>