Re: [syzbot] [netfilter?] WARNING in __nf_unregister_net_hook (9)

[syzbot <syzbot+78ac1e46d2966eb70fda@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in __nf_unregister_net_hook

------------[ cut here ]------------
hook not found, pf 5 num 0
WARNING: CPU: 1 PID: 9010 at net/netfilter/core.c:517 __nf_unregister_net_hook+0x328/0x740 net/netfilter/core.c:517
Modules linked in:
CPU: 1 UID: 0 PID: 9010 Comm: syz.0.750 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__nf_unregister_net_hook+0x328/0x740 net/netfilter/core.c:517
Code: 06 01 90 48 8b 44 24 08 42 0f b6 04 38 84 c0 0f 85 09 04 00 00 48 8b 04 24 8b 10 48 c7 c7 60 c0 b2 8c 89 ee e8 39 b6 e5 f7 90 <0f> 0b 90 90 e9 e9 01 00 00 e8 9a 07 e1 01 89 c3 31 ff 89 c6 e8 ef
RSP: 0018:ffffc90005016b38 EFLAGS: 00010246
RAX: 9d569200b7b5bf00 RBX: dffffc0000000000 RCX: ffff8880300a0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000005 R08: ffff8880b8724293 R09: 1ffff110170e4852
R10: dffffc0000000000 R11: ffffed10170e4853 R12: ffff888057f16580
R13: ffff88807af62480 R14: ffff888021be0488 R15: dffffc0000000000
FS:  00007fbad7ffe6c0(0000) GS:ffff888125be7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c008884020 CR3: 0000000075906000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nft_unregister_flowtable_ops net/netfilter/nf_tables_api.c:8979 [inline]
 nft_flowtable_event net/netfilter/nf_tables_api.c:9758 [inline]
 __nf_tables_flowtable_event+0x5bf/0x8c0 net/netfilter/nf_tables_api.c:9803
 nf_tables_flowtable_event+0x103/0x160 net/netfilter/nf_tables_api.c:9834
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 unregister_netdevice_many_notify+0x1863/0x23d0 net/core/dev.c:12333
 rtnl_newlink_create+0x84b/0xb70 net/core/rtnetlink.c:3861
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0x1663/0x1be0 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6951
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa84/0xaf0 net/socket.c:2630
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2719
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf0/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbad899aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbad7ffe028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbad8c15fa0 RCX: 00007fbad899aeb9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fbad8a08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbad8c16038 R14: 00007fbad8c15fa0 R15: 00007ffc697d6c08
 </TASK>


Tested on:

commit:         efd3e30e Merge branch 'net-stmmac-hwif-c-cleanups'
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12d20952580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=365838d2488d91f6
dashboard link: https://syzkaller.appspot.com/bug?extid=78ac1e46d2966eb70fda
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=117e755a580000