From: Ming Lei <ming.lei@redhat.com>
Date: Tue, 11 Jun 2019 09:31:53 +0000 (+0800)
Subject: blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=c326f846ebc2a30eca386b85dffba96e23803d81;p=openwrt%2Fstaging%2Fblogic.git

blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests

blk_mq_sched_free_requests() may be called in failure path in which
q->elevator may not be setup yet, so remove WARN_ON(!q->elevator) from
blk_mq_sched_free_requests for avoiding the false positive.

This function is actually safe to call in case of !q->elevator because
hctx->sched_tags is checked.

Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Yi Zhang <yi.zhang@redhat.com>
Fixes: c3e2219216c9 ("block: free sched's request pool in blk_cleanup_queue")
Reported-by: syzbot+b9d0d56867048c7bcfde@syzkaller.appspotmail.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 500cb04901cc..2766066a15db 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -555,7 +555,6 @@ void blk_mq_sched_free_requests(struct request_queue *q)
 	int i;
 
 	lockdep_assert_held(&q->sysfs_lock);
-	WARN_ON(!q->elevator);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (hctx->sched_tags)