Re: general protection fault in io_commit_cqring

[syzbot]

syzbot has bisected this bug to:

commit 1d7bb1d50fb4dc141c7431cc21fdd24ffcc83c76
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Wed Nov 6 18:31:17 2019 +0000

    io_uring: add support for backlogged CQ ring

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16a49802e00000
start commit:   4e8f108c Add linux-next specific files for 20191113
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=15a49802e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=11a49802e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ace1bcdd76242fd2
dashboard link: https://syzkaller.appspot.com/bug?extid=21147d79607d724bd6f3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1649e706e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11397f72e00000

Reported-by: syzbot+21147d79607d724bd6f3@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 1d7bb1d50fb4 ("io_uring: add support for backlogged CQ ring")

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