Re: [PATCH] perf: report: don't call map__kmap if map is NULL.

[Arnaldo Carvalho de Melo]

Em Wed, Apr 08, 2015 at 10:59:32AM +0000, Wang Nan escreveu:
> report__warn_kptr_restrict() calls map__kmap(kernel_map) before
> checking kernel_map againest NULL. Which is dangerous, since
> map__kmap() will return a invalid and not NULL address. It will trigger
> a warning message in map__kmap() after patch "perf: kmaps: enforce
> usage of kmaps to protect futher bugs."
> 
> This patch fixes it by adding the missing checking.
> 
> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> ---
>  tools/perf/builtin-report.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index b5b2ad4..476cdf7 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -347,7 +347,7 @@ static int perf_evlist__tty_browse_hists(struct perf_evlist *evlist,
>  static void report__warn_kptr_restrict(const struct report *rep)
>  {
>  	struct map *kernel_map = rep->session->machines.host.vmlinux_maps[MAP__FUNCTION];
> -	struct kmap *kernel_kmap = map__kmap(kernel_map);
> +	struct kmap *kernel_kmap = kernel_map ? map__kmap(kernel_map) : NULL;
>  
>  	if (kernel_map == NULL ||
>  	    (kernel_map->dso->hit &&

Thanks, applied.
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