Re: [PATCH 1/1] perf map: Fix error return code in maps__clone()

From: Arnaldo Carvalho de Melo
Date: Thu Apr 15 2021 - 08:42:53 EST


Em Thu, Apr 15, 2021 at 05:27:44PM +0800, Zhen Lei escreveu:
> Although 'err' has been initialized to -ENOMEM, but it will be reassigned
> by the "err = unwind__prepare_access(...)" statement in the for loop. So
> that, the value of 'err' is unknown when map__clone() failed.

You forgot to research and add this:

Fixes: 6c502584438bda63 ("perf unwind: Call unwind__prepare_access for forked thread")

So that the stable@xxxxxxxxxx guys can pick this up automagically and
apply this fix to the stable kernels.

I've added it.

Thanks, applied.

- Arnaldo

> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> ---
> tools/perf/util/map.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index fbc40a2c17d4dca..8af693d9678cefe 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -840,15 +840,18 @@ int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp)
> int maps__clone(struct thread *thread, struct maps *parent)
> {
> struct maps *maps = thread->maps;
> - int err = -ENOMEM;
> + int err;
> struct map *map;
>
> down_read(&parent->lock);
>
> maps__for_each_entry(parent, map) {
> struct map *new = map__clone(map);
> - if (new == NULL)
> +
> + if (new == NULL) {
> + err = -ENOMEM;
> goto out_unlock;
> + }
>
> err = unwind__prepare_access(maps, new, NULL);
> if (err)
> --
> 2.26.0.106.g9fadedd
>
>

--

- Arnaldo