INFO: rcu detected stall in exit_group

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 1d0e850a49a5b56f8f3cb51e74a11e2fedb96be6
Author: David Howells <dhowells at redhat.com>
Date:   Fri Oct 16 12:21:14 2020 +0000

    afs: Fix cell removal

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14b65c3a500000
start commit:   34d4ddd3 Merge tag 'linux-kselftest-5.9-rc5' of git://git...
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=a9075b36a6ae26c9
dashboard link: https://syzkaller.appspot.com/bug?extid=1a14a0f8ce1a06d4415f
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10c6642d900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=132d00fd900000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: afs: Fix cell removal

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