From 4a45a7dcc55e358d7757e31bdf2d53891343737b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 29 May 2022 07:13:09 -0600 Subject: [PATCH] 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@casper.infradead.org/ Reported-by: Matthew Wilcox Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/bio.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/bio.c b/block/bio.c index 9b28381412d23..8381c6690dd6c 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; } /**