On Sat, 21 Aug 2021 at 17:19, syzbot
[off-list ref] wrote:

Hello,

syzbot found the following issue on:

HEAD commit:    9803fb968c8c Add linux-next specific files for 20210817
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1727c65e300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=681282daead30d81
dashboard link: https://syzkaller.appspot.com/bug?extid=cd7ceee0d3b5892f07af
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13fb6ff9300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15272861300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cd7ceee0d3b5892f07af@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000

Looks like this was only ever hit in linux-next and fixed before it
got to mainline? Anyway, I can confirm the following patch fixes the
issue:

#syz fix: af_unix: Fix NULL pointer bug in unix_shutdown


Vegard