Re: KASAN: invalid-free in io_sqe_files_unregister

[syzbot]

syzbot has bisected this bug to:

commit 65e19f54d29cd8559ce60cfd0d751bef7afbdc5c
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Sat Oct 26 13:20:21 2019 +0000

    io_uring: support for larger fixed file sets

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=154f483ce00000
start commit:   5591cf00 Add linux-next specific files for 20191108
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=174f483ce00000
console output: https://syzkaller.appspot.com/x/log.txt?x=134f483ce00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e1036c6ef52866f9
dashboard link: https://syzkaller.appspot.com/bug?extid=3254bc44113ae1e331ee
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=116bb33ae00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173f133ae00000

Reported-by: syzbot+3254bc44113ae1e331ee@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 65e19f54d29c ("io_uring: support for larger fixed file sets")

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