blk-mq: fix NULL dereference on q->elevator in blk_mq_elv_switch_none
authorMing Lei <ming.lei@redhat.com>
Fri, 16 Jun 2023 13:23:54 +0000 (21:23 +0800)
committerJens Axboe <axboe@kernel.dk>
Fri, 16 Jun 2023 16:12:25 +0000 (10:12 -0600)
commit245165658e1c9f95c0fecfe02b9b1ebd30a1198a
tree0afb4aef73404f0134af73f0cfcab25953a39e0b
parent84bd06c632c6d5279849f5f8ab47d9517d259422
blk-mq: fix NULL dereference on q->elevator in blk_mq_elv_switch_none

After grabbing q->sysfs_lock, q->elevator may become NULL because of
elevator switch.

Fix the NULL dereference on q->elevator by checking it with lock.

Reported-by: Guangwu Zhang <guazhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230616132354.415109-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-mq.c