Re: [syzbot] KASAN: use-after-free Write in __io_free_req

[syzbot]

syzbot has bisected this issue to:

commit 34ced75ca1f63fac6148497971212583aa0f7a87
Author: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
Date:   Mon Oct 25 05:38:48 2021 +0000

    io_uring: reduce frequent add_wait_queue() overhead for multi-shot poll request

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14f83bbab00000
start commit:   bdcc9f6a5682 Add linux-next specific files for 20211029
git tree:       linux-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16f83bbab00000
console output: https://syzkaller.appspot.com/x/log.txt?x=12f83bbab00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cea91ee10b0cd274
dashboard link: https://syzkaller.appspot.com/bug?extid=78b76ebc91042904f34e
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10cf03e2b00000

Reported-by: syzbot+78b76ebc91042904f34e@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 34ced75ca1f6 ("io_uring: reduce frequent add_wait_queue() overhead for multi-shot poll request")

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