Re: [PATCH] perf: Add NULL pointer check for cpu_map iteration and NULL assignment for all_cpus.

[Jiri Olsa <jolsa@redhat.com>]

On Sun, Mar 08, 2020 at 06:59:17PM +0800, zhe.he@windriver.com wrote:
> From: He Zhe <zhe.he@windriver.com>
> 
> NULL pointer may be passed to perf_cpu_map__cpu and then cause crash,
> such as the one commit cb71f7d43ece ("libperf: Setup initial evlist::all_cpus value")
> fix.
> 
> Signed-off-by: He Zhe <zhe.he@windriver.com>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
>  tools/perf/lib/cpumap.c | 2 +-
>  tools/perf/lib/evlist.c | 1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/lib/cpumap.c b/tools/perf/lib/cpumap.c
> index f93f4e7..ca02150 100644
> --- a/tools/perf/lib/cpumap.c
> +++ b/tools/perf/lib/cpumap.c
> @@ -247,7 +247,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
>  
>  int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
>  {
> -	if (idx < cpus->nr)
> +	if (cpus && idx < cpus->nr)
>  		return cpus->map[idx];
>  
>  	return -1;
> diff --git a/tools/perf/lib/evlist.c b/tools/perf/lib/evlist.c
> index 5b9f2ca..f87a239 100644
> --- a/tools/perf/lib/evlist.c
> +++ b/tools/perf/lib/evlist.c
> @@ -127,6 +127,7 @@ void perf_evlist__exit(struct perf_evlist *evlist)
>  	perf_cpu_map__put(evlist->cpus);
>  	perf_thread_map__put(evlist->threads);
>  	evlist->cpus = NULL;
> +	evlist->all_cpus = NULL;
>  	evlist->threads = NULL;
>  	fdarray__exit(&evlist->pollfd);
>  }
> -- 
> 2.7.4
>