Re: WARNING in iov_iter_revert (2)

[syzbot]

syzbot has bisected this issue to:

commit 9bb48c82aced07698a2d08ee0f1475a6c4f6b266
Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date:   Tue Jan 19 19:41:16 2021 +0000

    tty: implement write_iter

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1009a9f2d00000
start commit:   dcc0b490 Merge tag 'powerpc-5.11-8' of git://git.kernel.or..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1209a9f2d00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1409a9f2d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1106b4b91e8dfab8
dashboard link: https://syzkaller.appspot.com/bug?extid=3d2c27c2b7dc2a94814d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1346ac60d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=123eae4cd00000

Reported-by: syzbot+3d2c27c2b7dc2a94814d@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 9bb48c82aced ("tty: implement write_iter")

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