From 284b94be1925dbe035ce5218d8b5c197321262c7 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 26 Sep 2019 06:23:54 +0800 Subject: [PATCH] blk-mq: move lockdep_assert_held() into elevator_exit 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 Reviewed-by: Damien Le Moal Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- 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 c9d183d6c499..ca22afd47b3d 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 ed347f7a97b1..25773d668ec0 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); }