From: Jens Axboe axboe@kernel.dk
[ Upstream commit 947b7ac135b16aa60f9141ff72bd494eda0edb5e ]
We can't touch a bio after ->make_request_fn(), for all we know it could already have been completed by the time this function returns.
This reverts commit 698cef173983b086977e633e46476e0f925ca01e.
Reported-by: syzbot+4df6ca820108fd248943@syzkaller.appspotmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-core.c | 11 ----------- block/blk-merge.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index 22260339f66f..deb56932f8c4 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2449,18 +2449,7 @@ blk_qc_t generic_make_request(struct bio *bio) /* Create a fresh bio_list for all subordinate requests */ bio_list_on_stack[1] = bio_list_on_stack[0]; bio_list_init(&bio_list_on_stack[0]); - - /* - * Since we're recursing into make_request here, ensure - * that we mark this bio as already having entered the queue. - * If not, and the queue is going away, we can get stuck - * forever on waiting for the queue reference to drop. But - * that will never happen, as we're already holding a - * reference to it. - */ - bio_set_flag(bio, BIO_QUEUE_ENTERED); ret = q->make_request_fn(q, bio); - bio_clear_flag(bio, BIO_QUEUE_ENTERED);
/* sort new bios into those for a lower level * and those for the same level diff --git a/block/blk-merge.c b/block/blk-merge.c index adfe835ab258..7695034f4b87 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -272,6 +272,16 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* there isn't chance to merge the splitted bio */ split->bi_opf |= REQ_NOMERGE;
+ /* + * Since we're recursing into make_request here, ensure + * that we mark this bio as already having entered the queue. + * If not, and the queue is going away, we can get stuck + * forever on waiting for the queue reference to drop. But + * that will never happen, as we're already holding a + * reference to it. + */ + bio_set_flag(*bio, BIO_QUEUE_ENTERED); + bio_chain(split, *bio); trace_block_split(q, split, (*bio)->bi_iter.bi_sector); generic_make_request(*bio);