Subject: [syzbot] WARNING in nfnetlink_unbind

From: syzbot <[email-masked]>
Date: Tue, 17 May 2022 11:12:21 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    f7b88d9ae91e Merge tag 'linux-can-next-for-5.19-20220516' ..
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14f791aef00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c05eee2efc702eed
dashboard link: https://syzkaller.appspot.com/bug?extid=afd2d80e495f96049571
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13ba8ae9f00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ef1295f00000

The issue was bisected to:

commit 2794cdb0b97bfe62d25c996c8afe4832207e78bc
Author: Florian Westphal <[email-masked]>
Date:   Mon Apr 25 13:15:41 2022 +0000

    netfilter: nfnetlink: allow to detect if ctnetlink listeners exist

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13cb5bbef00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=102b5bbef00000
console output: https://syzkaller.appspot.com/x/log.txt?x=17cb5bbef00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: 2794cdb0b97b ("netfilter: nfnetlink: allow to detect if ctnetlink listeners exist")

------------[ cut here ]------------
WARNING: CPU: 0 PID: 3600 at net/netfilter/nfnetlink.c:703 nfnetlink_unbind net/netfilter/nfnetlink.c:703 [inline]
WARNING: CPU: 0 PID: 3600 at net/netfilter/nfnetlink.c:703 nfnetlink_unbind+0x357/0x3b0 net/netfilter/nfnetlink.c:694
Modules linked in:
CPU: 0 PID: 3600 Comm: syz-executor186 Not tainted 5.18.0-rc6-syzkaller-01545-gf7b88d9ae91e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:nfnetlink_unbind net/netfilter/nfnetlink.c:703 [inline]
RIP: 0010:nfnetlink_unbind+0x357/0x3b0 net/netfilter/nfnetlink.c:694
Code: f9 48 c7 c2 00 0d d8 8a be b7 02 00 00 48 c7 c7 60 0d d8 8a c6 05 91 3d 14 06 01 e8 38 36 9b 01 e9 6e fd ff ff e8 09 66 e8 f9 <0f> 0b 41 c7 04 24 ff ff ff ff e9 9d fe ff ff e8 a5 7a 34 fa e9 dd
RSP: 0018:ffffc90002e8fcf8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88801bd11d80 RSI: ffffffff8790d397 RDI: 0000000000000003
RBP: ffffffff90947640 R08: 0000000000000000 R09: ffffc90002e8fc37
R10: ffffffff8790d1e8 R11: 0000000000000001 R12: ffff8880230b4d20
R13: ffff88814c73b000 R14: ffff888016aab518 R15: ffff888016aab000
FS:  0000555557248300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001280 CR3: 000000001f866000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 netlink_setsockopt+0x932/0xda0 net/netlink/af_netlink.c:1661
 __sys_setsockopt+0x2db/0x6a0 net/socket.c:2227
 __do_sys_setsockopt net/socket.c:2238 [inline]
 __se_sys_setsockopt net/socket.c:2235 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2235
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f37f8e5faf9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef051fc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f37f8e5faf9
RDX: 0000000000000002 RSI: 000000000000010e RDI: 0000000000000003
RBP: 00007f37f8e23ca0 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000020001280 R11: 0000000000000246 R12: 00007f37f8e23d30
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

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