lkml.org 
[lkml]   [2024]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 1/1] perf probe: Use zfree() to avoid possibly accessing dangling pointers
On Tue, May 7, 2024 at 7:58 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> When freeing a->b it is good practice to set a->b to NULL using
> zfree(&a->b) so that when we have a bug where a reference to a freed 'a'
> pointer is kept somewhere, we can more quickly cause a segfault if some
> code tries to use a->b.
>
> Convert one such case in the 'perf probe' codebase.
>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/builtin-probe.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 019fef8da6a8e60f..003a3bcebfdfc2d1 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -325,7 +325,7 @@ static void cleanup_params(void)
> for (i = 0; i < params->nevents; i++)
> clear_perf_probe_event(params->events + i);
> line_range__clear(&params->line_range);
> - free(params->target);
> + zfree(&params->target);
> strfilter__delete(params->filter);
> nsinfo__put(params->nsi);
> zfree(&params);

The change is fine but params is freed here, so the potential to read
"->target" is small.

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> --
> 2.44.0
>

\
 
 \ /
  Last update: 2024-05-09 08:43    [W:2.797 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site