Re: WARNING in __blk_mq_delay_run_hw_queue

[syzbot]

syzbot has bisected this bug to:

commit ed76e329d74a4b15ac0f5fd3adbd52ec0178a134
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Mon Oct 29 19:06:14 2018 +0000

    blk-mq: abstract out queue map

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1558f6fb600000
start commit:   b145b0eb Merge tag 'for-linus' of git://git.kernel.org/pub..
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1758f6fb600000
console output: https://syzkaller.appspot.com/x/log.txt?x=1358f6fb600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1ec3be9936e004f6
dashboard link: https://syzkaller.appspot.com/bug?extid=d44e1b26ce5c3e77458d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=165fcefb600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=162d03db600000

Reported-by: syzbot+d44e1b26ce5c3e77458d@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: ed76e329d74a ("blk-mq: abstract out queue map")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection