From 947b7ac135b16aa60f9141ff72bd494eda0edb5e Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 27 Jan 2019 06:35:28 -0700 Subject: [PATCH] Revert "block: cover another queue enter recursion via BIO_QUEUE_ENTERED" 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 --- 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 1ccec27d20c3..3c5f61ceeb67 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1083,18 +1083,7 @@ 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 d79a22f111d1..71e9ac03f621 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);