BUG: unable to handle kernel NULL pointer dereference in corrupted (4)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 4b972a01 Linux 5.2-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17852b6ea00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e7c31a94f66cc0aa
dashboard link: https://syzkaller.appspot.com/bug?extid=4b5d77fdf765668f9eba
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15252769a00000

The bug was bisected to:

commit e9db4ef6bf4ca9894bb324c76e01b8f1a16b2650
Author: John Fastabend <john.fa...@gmail.com>
Date: Sat Jun 30 13:17:47 2018 +0000

bpf: sockhash fix omitted bucket lock in sock_close

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=146ae35ea00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=166ae35ea00000
console output: https://syzkaller.appspot.com/x/log.txt?x=126ae35ea00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4b5d77...@syzkaller.appspotmail.com
Fixes: e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close")

BUG: kernel NULL pointer dereference, address: 00000000000000fc


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Eric Biggers]

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#syz fix: bpf: sockmap/tls, close can race with map free