From: Ming Lei ming.lei@redhat.com
[ Upstream commit 284b94be1925dbe035ce5218d8b5c197321262c7 ]
Commit c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq") removes q->sysfs_lock from elevator_init_mq(), but forgot to deal with lockdep_assert_held() called in blk_mq_sched_free_requests() which is run in failure path of elevator_init_mq().
blk_mq_sched_free_requests() is called in the following 3 functions:
elevator_init_mq() elevator_exit() blk_cleanup_queue()
In blk_cleanup_queue(), blk_mq_sched_free_requests() is followed exactly by 'mutex_lock(&q->sysfs_lock)'.
So moving the lockdep_assert_held() from blk_mq_sched_free_requests() into elevator_exit() for fixing the report by syzbot.
Reported-by: syzbot+da3b7677bb913dc1b737@syzkaller.appspotmail.com Fixed: c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq") Reviewed-by: Bart Van Assche bvanassche@acm.org Reviewed-by: Damien Le Moal damien.lemoal@wdc.com Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq-sched.c | 2 -- block/blk.h | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index c9d183d6c4999..ca22afd47b3dc 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -555,8 +555,6 @@ void blk_mq_sched_free_requests(struct request_queue *q) struct blk_mq_hw_ctx *hctx; int i;
- lockdep_assert_held(&q->sysfs_lock); - queue_for_each_hw_ctx(q, hctx, i) { if (hctx->sched_tags) blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i); diff --git a/block/blk.h b/block/blk.h index de6b2e146d6eb..3ce8b73bb2264 100644 --- a/block/blk.h +++ b/block/blk.h @@ -194,6 +194,8 @@ void elv_unregister_queue(struct request_queue *q); static inline void elevator_exit(struct request_queue *q, struct elevator_queue *e) { + lockdep_assert_held(&q->sysfs_lock); + blk_mq_sched_free_requests(q); __elevator_exit(q, e); }