This is a note to let you know that I've just added the patch titled block: make bioset_exit() fully resilient against being called twice to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: block-make-bioset_exit-fully-resilient-against-being.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a699a172d4ccb4061c35011f9dac40c33b3b831a Author: Jens Axboe <axboe@xxxxxxxxx> Date: Sun May 29 07:13:09 2022 -0600 block: make bioset_exit() fully resilient against being called twice [ Upstream commit 605f7415ecfb426610195dd6c7577b30592b3369 ] Most of bioset_exit() is fine being called twice, as it clears the various allocations etc when they are freed. The exception is bio_alloc_cache_destroy(), which does not clear ->cache when it has freed it. This isn't necessarily a bug, but can be if buggy users does call the exit path more then once, or with just a memset() bioset which has never been initialized. dm appears to be one such user. Fixes: be4d234d7aeb ("bio: add allocation cache abstraction") Link: https://lore.kernel.org/linux-block/YpK7m+14A+pZKs5k@xxxxxxxxxxxxxxxxxxxx/ Reported-by: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/block/bio.c b/block/bio.c index 9b28381412d2..8381c6690dd6 100644 --- a/block/bio.c +++ b/block/bio.c @@ -665,6 +665,7 @@ static void bio_alloc_cache_destroy(struct bio_set *bs) bio_alloc_cache_prune(cache, -1U); } free_percpu(bs->cache); + bs->cache = NULL; } /**