syzbot


WARNING in __nf_unregister_net_hook (9)

Status: upstream: reported syz repro on 2025/07/30 05:30
Subsystems: netfilter
[Documentation on labels]
Reported-by: syzbot+78ac1e46d2966eb70fda@syzkaller.appspotmail.com
First crash: 222d, last: 13h07m
Cause bisection: failed (error log, bisect log)
  
Discussions (5)
Title Replies (including bot) Last reply
[syzbot] [netfilter?] WARNING in __nf_unregister_net_hook (9) 1 (10) 2026/02/27 12:46
[syzbot] Monthly netfilter report (Feb 2026) 0 (1) 2026/02/26 12:58
[syzbot] Monthly netfilter report (Dec 2025) 0 (1) 2025/12/26 07:47
[syzbot] Monthly netfilter report (Nov 2025) 0 (1) 2025/11/24 12:38
[syzbot] Monthly netfilter report (Sep 2025) 0 (1) 2025/09/20 18:33
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __nf_unregister_net_hook (4) netfilter -1 C error 66 1460d 1790d 20/29 fixed on 2022/03/08 16:11
upstream WARNING in __nf_unregister_net_hook netfilter -1 1 2142d 2137d 0/29 auto-closed as invalid on 2020/06/22 17:41
upstream WARNING in __nf_unregister_net_hook (6) netfilter -1 C error 2 753d 870d 25/29 fixed on 2024/03/26 17:39
upstream WARNING in __nf_unregister_net_hook (8) netfilter -1 2 327d 339d 28/29 fixed on 2025/06/10 16:19
upstream WARNING in __nf_unregister_net_hook (7) netfilter -1 2 512d 512d 0/29 auto-obsoleted due to no activity on 2025/01/17 09:21
upstream WARNING in __nf_unregister_net_hook (5) netfilter -1 183 1373d 1457d 0/29 auto-closed as invalid on 2022/07/31 13:33
upstream WARNING in __nf_unregister_net_hook (2) netfilter -1 C done 9 2062d 2060d 15/29 fixed on 2020/09/16 22:51
upstream WARNING in __nf_unregister_net_hook (3) netfilter -1 1 1995d 1995d 0/29 auto-closed as invalid on 2020/12/16 11:13
Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/02/27 12:46 23m phil@nwl.cc net-next report log
2026/02/27 10:25 1h26m phil@nwl.cc patch git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git efd3e30e651d report log
2026/02/26 16:39 28m phil@nwl.cc patch net-next OK log
2026/02/15 23:43 22m retest repro net-next report log
2026/02/15 23:29 22m retest repro net-next report log
2026/01/18 04:42 1h21m retest repro net-next report log
2026/01/16 13:57 1h02m phil@nwl.cc patch net-next report log
2025/10/31 16:16 2h28m phil@nwl.cc net-next report log
2025/10/31 10:22 21m phil@nwl.cc net-next report log
2025/10/31 01:04 25m phil@nwl.cc patch net-next OK log

Sample crash report:
------------[ cut here ]------------
hook not found, pf 5 num 0
WARNING: net/netfilter/core.c:514 at __nf_unregister_net_hook+0x2c5/0x6f0 net/netfilter/core.c:514, CPU#1: syz.2.265/6891
Modules linked in:
CPU: 1 UID: 0 PID: 6891 Comm: syz.2.265 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__nf_unregister_net_hook+0x2dc/0x6f0 net/netfilter/core.c:514
Code: 24 30 48 8b 5c 24 08 44 8b 6c 24 04 48 8d 3d 1b 62 4a 06 48 8b 44 24 10 0f b6 04 28 84 c0 0f 85 f1 02 00 00 41 8b 17 44 89 ee <67> 48 0f b9 3a e9 db 01 00 00 e8 45 e0 e4 01 89 c3 31 ff 89 c6 e8
RSP: 0018:ffffc9000ca5eb38 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888034565d00 RCX: ffff88805a509e80
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffffffff8ffe3640
RBP: dffffc0000000000 R08: ffffffff8fef3477 R09: 1ffffffff1fde68e
R10: dffffc0000000000 R11: fffffbfff1fde68f R12: ffff888057808000
R13: 0000000000000005 R14: ffff88807e14c490 R15: ffff88802e67873c
FS:  00007fd3d32136c0(0000) GS:ffff8881257ed000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000200 CR3: 0000000074ab4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nft_unregister_flowtable_ops net/netfilter/nf_tables_api.c:9041 [inline]
 nft_flowtable_event net/netfilter/nf_tables_api.c:9820 [inline]
 __nf_tables_flowtable_event+0x5bf/0x8c0 net/netfilter/nf_tables_api.c:9865
 nf_tables_flowtable_event+0x103/0x160 net/netfilter/nf_tables_api.c:9896
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2280 [inline]
 call_netdevice_notifiers net/core/dev.c:2294 [inline]
 unregister_netdevice_many_notify+0x186a/0x2370 net/core/dev.c:12398
 rtnl_newlink_create+0x84b/0xb70 net/core/rtnetlink.c:3868
 __rtnl_newlink net/core/rtnetlink.c:3957 [inline]
 rtnl_newlink+0x1666/0x1be0 net/core/rtnetlink.c:4072
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
 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+0xa68/0xad0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd3d239aeb9
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:00007fd3d3213028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd3d2615fa0 RCX: 00007fd3d239aeb9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fd3d2408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd3d2616038 R14: 00007fd3d2615fa0 R15: 00007ffd29ee8b38
 </TASK>
----------------
Code disassembly (best guess):
   0:	24 30                	and    $0x30,%al
   2:	48 8b 5c 24 08       	mov    0x8(%rsp),%rbx
   7:	44 8b 6c 24 04       	mov    0x4(%rsp),%r13d
   c:	48 8d 3d 1b 62 4a 06 	lea    0x64a621b(%rip),%rdi        # 0x64a622e
  13:	48 8b 44 24 10       	mov    0x10(%rsp),%rax
  18:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax
  1c:	84 c0                	test   %al,%al
  1e:	0f 85 f1 02 00 00    	jne    0x315
  24:	41 8b 17             	mov    (%r15),%edx
  27:	44 89 ee             	mov    %r13d,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 db 01 00 00       	jmp    0x20f
  34:	e8 45 e0 e4 01       	call   0x1e4e07e
  39:	89 c3                	mov    %eax,%ebx
  3b:	31 ff                	xor    %edi,%edi
  3d:	89 c6                	mov    %eax,%esi
  3f:	e8                   	.byte 0xe8

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/01 23:22 net-next a22f57757f7e 6b8752f2 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
2025/10/30 12:36 net-next efd3e30e651d fd2207e7 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
2026/01/04 02:14 upstream aacb0a6d604a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in __nf_unregister_net_hook
2025/11/14 10:42 upstream 6da43bbeb691 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in __nf_unregister_net_hook
2025/11/02 07:42 upstream 691d401c7e0e 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in __nf_unregister_net_hook
2025/12/23 23:31 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in __nf_unregister_net_hook
2025/11/13 23:24 upstream 2ccec5944606 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in __nf_unregister_net_hook
2025/12/08 06:43 upstream c2f2b01b74be d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in __nf_unregister_net_hook
2025/11/13 19:30 net fe82c4f8a228 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in __nf_unregister_net_hook
2026/03/05 13:35 bpf-next 4faa1893807c d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-next-kasan-gce WARNING in __nf_unregister_net_hook
2026/02/23 03:47 bpf-next 9cd168a2720b 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-next-kasan-gce WARNING in __nf_unregister_net_hook
2025/12/10 05:14 net-next 8f7aa3d3c732 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
2025/09/11 02:59 net-next 38611e5adae3 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
2025/09/11 02:59 net-next 38611e5adae3 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
2025/07/26 05:18 net-next 9312ee76490d fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in __nf_unregister_net_hook
* Struck through repros no longer work on HEAD.