Em Mon, Jan 20, 2020 at 05:15:54PM +0300, Cengiz Can escreveu:
> `tools/perf/util/map.c` has a function named `maps__insert` that
> acquires a write lock if its in multithread context.
>
> Even though this lock is released when function successfully completes,
> there's a branch that is executed when `maps_by_name == NULL` that
> returns from this function without releasing the write lock.
>
> Added an `up_write` to release the lock when this happens.
>
> Signed-off-by: Cengiz Can <cengiz@xxxxxxxxxx>
> ---
>
> Hello Arnaldo,
>
> I'm not exactly sure about the order that we must call up_write here.
>
> Please tell me if the `__maps__free_maps_by_name` frees the
> `rw_semaphore`. If that's the case, should we change the order to unlock and free?
No it doesn't free the rw_semaphore, that is in 'struct maps', what is
being freed is just something protected by rw_semaphore,
maps->maps_by_name, so your patch is right and I'm applying it, thanks.
- Arnaldo
> Thanks!
>
> tools/perf/util/map.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index fdd5bddb3075..f67960bedebb 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -549,6 +549,7 @@ void maps__insert(struct maps *maps, struct map *map)
>
> if (maps_by_name == NULL) {
> __maps__free_maps_by_name(maps);
> + up_write(&maps->lock);
> return;
> }
>
> --
> 2.25.0
>
--
- Arnaldo
