From: Ming Lei <ming.lei@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixed: c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq")
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 d5edfd73d45ea..0685c45e3d96e 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -201,6 +201,8 @@ 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);
}
--
2.20.1
