From 4d337cebcb1c27d9b48c48b9a98e939d4552d584 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 16 Jun 2022 09:44:00 +0800 Subject: blk-mq: avoid to touch q->elevator without any protection q->elevator is referred in blk_mq_has_sqsched() without any protection, no .q_usage_counter is held, no queue srcu and rcu read lock is held, so potential use-after-free may be triggered. Fix the issue by adding one queue flag for checking if the elevator uses single queue style dispatch. Meantime the elevator feature flag of ELEVATOR_F_MQ_AWARE isn't needed any more. Cc: Jan Kara Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220616014401.817001-3-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/bfq-iosched.c') diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 0d46cb728bbf..caa55a5624bc 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -7188,6 +7188,9 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) bfq_init_root_group(bfqd->root_group, bfqd); bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group); + /* We dispatch from request queue wide instead of hw queue */ + blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q); + wbt_disable_default(q); return 0; -- cgit v1.2.3