WARNING in nf_conntrack_cleanup_net_list (2)

Status: upstream: reported on 2026/05/29 20:02
Subsystems: netfilter
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+122256c3e2bf6ec9f928@syzkaller.appspotmail.com
First crash: 165d, last: 3d07h
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
6f1f5e68 repro-c 💥 WARNING in nf_conntrack_cleanup_net_list (2) 2026/10/19 02:11 2026/10/19 02:11 2026/10/19 03:45 432c0077
8402b387 repro-c 💥 WARNING in nf_conntrack_cleanup_net_list (2) 2026/10/17 02:32 2026/10/17 02:32 2026/10/17 03:48 432c0077
5c37299a assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in nf_conntrack_cleanup_net_list (2) 2026/05/29 23:15 2026/05/29 23:15 2026/05/29 23:51 6b4a8443
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[syzbot] Monthly netfilter report (Nov 2026) 0 (1) 2026/11/03 04:33
[syzbot] Monthly netfilter report (Aug 2026) 0 (1) 2026/08/02 00:00
[syzbot] Monthly netfilter report (Jul 2026) 0 (1) 2026/07/01 12:32
[syzbot] [netfilter?] WARNING in nf_conntrack_cleanup_net_list (2) 0 (1) 2026/05/29 20:02
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in nf_conntrack_cleanup_net_list netfilter -1 765 197d 332d 29/29 fixed on 2026/05/06 16:40

Sample crash report:
------------[ cut here ]------------
conntrack cleanup blocked for 60s
WARNING: net/netfilter/nf_conntrack_core.c:2504 at nf_conntrack_cleanup_net_list+0x21a/0x370 net/netfilter/nf_conntrack_core.c:2503, CPU#1: kworker/u8:6/161
Modules linked in:
CPU: 1 UID: 0 PID: 161 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: netns cleanup_net
RIP: 0010:nf_conntrack_cleanup_net_list+0x21a/0x370 net/netfilter/nf_conntrack_core.c:2503
Code: 4c 89 ef e8 b8 1a 24 f8 4d 8b 7d 00 4d 39 ef 74 69 e8 aa db ac f7 45 31 e4 e9 aa fe ff ff e8 9d db ac f7 48 8d 3d 76 82 b1 07 <67> 48 0f b9 3a eb c0 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c da fe ff
RSP: 0018:ffffc90002f2f8b0 EFLAGS: 00010293
RAX: ffffffff8a1c3403 RBX: dffffc0000000000 RCX: ffff88801f395dc0
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: ffffffff91cdb680
RBP: 0000000000000001 R08: ffff88807e6fa803 R09: 1ffff1100fcdf500
R10: dffffc0000000000 R11: ffffed100fcdf501 R12: 0000000100001a7e
R13: ffffc90002f2fa50 R14: ffffc90002f2fa50 R15: 0000000100001a7f
FS:  0000000000000000(0000) GS:ffff888123510000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c307ebc CR3: 000000002d856000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ops_exit_list net/core/net_namespace.c:206 [inline]
 ops_undo_list+0x4d7/0x8f0 net/core/net_namespace.c:253
 cleanup_net+0x572/0x810 net/core/net_namespace.c:708
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	4c 89 ef             	mov    %r13,%rdi
   3:	e8 b8 1a 24 f8       	call   0xf8241ac0
   8:	4d 8b 7d 00          	mov    0x0(%r13),%r15
   c:	4d 39 ef             	cmp    %r13,%r15
   f:	74 69                	je     0x7a
  11:	e8 aa db ac f7       	call   0xf7acdbc0
  16:	45 31 e4             	xor    %r12d,%r12d
  19:	e9 aa fe ff ff       	jmp    0xfffffec8
  1e:	e8 9d db ac f7       	call   0xf7acdbc0
  23:	48 8d 3d 76 82 b1 07 	lea    0x7b18276(%rip),%rdi        # 0x7b182a0
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb c0                	jmp    0xfffffff1
  31:	89 e9                	mov    %ebp,%ecx
  33:	80 e1 07             	and    $0x7,%cl
  36:	80 c1 03             	add    $0x3,%cl
  39:	38 c1                	cmp    %al,%cl
  3b:	0f                   	.byte 0xf
  3c:	8c da                	mov    %ds,%edx
  3e:	fe                   	(bad)
  3f:	ff                   	.byte 0xff

Crashes (108):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/05 03:30 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/04 12:26 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/30 10:45 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/30 05:54 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/28 15:28 upstream 65ba8f34ec88 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in nf_conntrack_cleanup_net_list
2026/10/28 07:51 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 16:46 upstream d135ab453a74 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/23 19:38 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/23 01:16 upstream 2a08195e4db5 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/17 07:22 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/16 17:44 upstream 2f2f7eeef8b0 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/07/26 20:54 upstream 3dab139d4795 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in nf_conntrack_cleanup_net_list
2026/10/17 12:00 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in nf_conntrack_cleanup_net_list
2026/10/27 01:37 upstream d135ab453a74 168cb7a2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nf_conntrack_cleanup_net_list
2026/10/26 11:25 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nf_conntrack_cleanup_net_list
2026/10/25 19:06 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nf_conntrack_cleanup_net_list
2026/05/27 09:38 upstream d60ec36cab33 2b01f00e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nf_conntrack_cleanup_net_list
2026/10/20 06:55 upstream c03c1a14507d 21286ae2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in nf_conntrack_cleanup_net_list
2026/11/02 05:47 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 23:47 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 22:37 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 16:26 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 14:32 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 12:28 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/01 08:28 net cb284914e749 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/31 21:12 net cb284914e749 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/31 16:38 net cb284914e749 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/31 13:53 net cb284914e749 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/31 00:00 net d8a4f4c59da5 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/30 13:10 net 5838f10563d5 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/30 06:51 net 5838f10563d5 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/30 00:30 net dda51b737216 b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/29 22:46 net dda51b737216 b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/29 07:58 net fd1436a75ceb b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/29 06:38 net fd1436a75ceb b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/29 03:04 net fd1436a75ceb b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/29 01:33 net fd1436a75ceb 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/28 20:44 net 5d7f3375cd57 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/28 17:23 net 5d7f3375cd57 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/28 11:07 net 5d7f3375cd57 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/28 09:26 net 5d7f3375cd57 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 19:40 net f75062536e2d 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 11:53 net 4dca97647a3e 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 07:53 net 4dca97647a3e 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 05:55 net 4dca97647a3e 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/27 00:04 net 6430fb7f1cc4 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/26 22:45 net 6430fb7f1cc4 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/26 20:16 net 6430fb7f1cc4 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/24 03:31 net 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/23 17:13 net 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/23 15:29 net 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/23 14:48 net 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/05 16:17 net-next 4bca33ba24db 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/05 11:59 net-next 7b6ab4dbc156 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/11/04 07:18 net-next 7b6ab4dbc156 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nf_conntrack_cleanup_net_list
2026/10/22 10:00 linux-next 9a482184d910 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2026/11/04 08:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 6628e7d4c6b2 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in nf_conntrack_cleanup_net_list
2026/10/30 02:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in nf_conntrack_cleanup_net_list
* Struck through repros no longer work on HEAD.