Re: [PATCH] perf: Fix sigbus with perf-top

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Feb 18, 2015 at 07:03:18PM -0500, David Ahern escreveu:
> perf-top is terminating due to SIGBUS on sparc64. git bisect points to:
> 
>     commit 82396986032915c1572bfb74b224fcc2e4e8ba7c
>     Author: Arnaldo Carvalho de Melo <acme@redhat.com>
>     Date:   Mon Sep 8 13:26:35 2014 -0300
> 
>         perf evlist: Refcount mmaps
> 
>         We need to know how many fds are using a perf mmap via
>         PERF_EVENT_IOC_SET_OUTPUT, so that we can know when to ditch an mmap,
>         refcount it.
> 
> This commit added 'int refcnt' to struct perf_mmap and the addition makes the
> event_copy element no longer 8-byte aligned. Fix by adding a pad.

I am applying this, but please consider doing like the kernel and using
one of those __aligned_on_foo struct member attributes.

I am adding a comment right after that pad...

- Arnaldo
 
> Signed-off-by: David Ahern <david.ahern@oracle.com>
> ---
>  tools/perf/util/evlist.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index c94a9e03ecf1..7a5a77b2b907 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -28,6 +28,7 @@ struct perf_mmap {
>  	int		 mask;
>  	int		 refcnt;
>  	unsigned int	 prev;
> +	int		 pad;
>  	char		 event_copy[PERF_SAMPLE_MAX_SIZE];
>  };
>  
> -- 
> 1.9.3