[PATCH AUTOSEL 6.0 34/34] bio: safeguard REQ_ALLOC_CACHE bio put

Sasha Levin
2022-11-01T11:31:21Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit d4347d50407daea6237872281ece64c4bdf1ec99 ]

bio_put() with REQ_ALLOC_CACHE assumes that it's executed not from
an irq context. Let's add a warning if the invariant is not respected,
especially since there is a couple of places removing REQ_POLLED by hand
without also clearing REQ_ALLOC_CACHE.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/558d78313476c4e9c233902efa0092644c3d420a.1666122465.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/bio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index 77e3b764a078..fc2364cf1775 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -741,7 +741,7 @@ void bio_put(struct bio *bio)
return;
}

- if (bio->bi_opf & REQ_ALLOC_CACHE) {
+ if ((bio->bi_opf & REQ_ALLOC_CACHE) && !WARN_ON_ONCE(in_interrupt())) {
struct bio_alloc_cache *cache;

bio_uninit(bio);
--
2.35.1