Re: BUG: unable to handle kernel paging request in io_wq_cancel_all

[syzbot]

syzbot has bisected this bug to:

commit ef0524d3654628ead811f328af0a4a2953a8310f
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Thu Oct 24 13:25:42 2019 +0000

    io_uring: replace workqueue usage with io-wq

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16acf5d0e00000
start commit:   c57cf383 Add linux-next specific files for 20191029
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=15acf5d0e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=11acf5d0e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb86688f30db053d
dashboard link: https://syzkaller.appspot.com/bug?extid=221cc24572a2fed23b6b
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=168671d4e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140f4898e00000

Reported-by: syzbot+221cc24572a2fed23b6b@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: ef0524d36546 ("io_uring: replace workqueue usage with io-wq")

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