From: Jens Axboe axboe@kernel.dk
[ 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 willy@infradead.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/bio.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/block/bio.c b/block/bio.c index ac29c87c6735..d3ca79c3ebdf 100644 --- a/block/bio.c +++ b/block/bio.c @@ -693,6 +693,7 @@ static void bio_alloc_cache_destroy(struct bio_set *bs) bio_alloc_cache_prune(cache, -1U); } free_percpu(bs->cache); + bs->cache = NULL; }
/**