Re: KASAN: slab-out-of-bounds Write in watch_queue_ioctl

[syzbot]

syzbot has bisected this bug to:

commit fe78d401ca6b3639385cf7a9a1597b9cd48f64eb
Author: David Howells <dhowells@xxxxxxxxxx>
Date:   Fri Oct 11 07:48:08 2019 +0000

    General notification queue with user mmap()'able ring buffer

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1163cafee00000
start commit:   fca4fe89 Add linux-next specific files for 20191217
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1363cafee00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1563cafee00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=634b7ce01f79423d
dashboard link: https://syzkaller.appspot.com/bug?extid=5a774ffe70862ca9ebc7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13df92fee00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1003cafee00000

Reported-by: syzbot+5a774ffe70862ca9ebc7@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: fe78d401ca6b ("General notification queue with user mmap()'able ring  
buffer")

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