syzbot


WARNING in nf_conntrack_cleanup_net_list

Status: upstream: reported on 2025/12/11 18:38
Subsystems: netfilter
[Documentation on labels]
Reported-by: syzbot+4393c47753b7808dac7d@syzkaller.appspotmail.com
First crash: 1d01h, last: 2h51m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [netfilter?] WARNING in nf_conntrack_cleanup_net_list 0 (1) 2025/12/11 18:38

Sample crash report:
------------[ cut here ]------------
conntrack cleanup blocked for 60s
WARNING: net/netfilter/nf_conntrack_core.c:2512 at nf_conntrack_cleanup_net_list+0x234/0x340 net/netfilter/nf_conntrack_core.c:2511, CPU#1: kworker/u8:17/6117
Modules linked in:
CPU: 1 UID: 0 PID: 6117 Comm: kworker/u8:17 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:nf_conntrack_cleanup_net_list+0x234/0x340 net/netfilter/nf_conntrack_core.c:2511
Code: 08 48 89 df e8 6d 7b a3 f8 4c 8b 3b 49 39 df 74 69 e8 90 18 3d f8 45 31 e4 e9 8e fe ff ff e8 83 18 3d f8 48 8d 3d 5c 31 0c 06 <67> 48 0f b9 3a eb c0 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c cd fe ff
RSP: 0018:ffffc9000b547870 EFLAGS: 00010293
RAX: ffffffff89849ecd RBX: ffffc9000b547a00 RCX: ffff88802a049e80
RDX: 0000000000000000 RSI: fffffffffffffffe RDI: ffffffff8f90d030
RBP: 0000000000000001 R08: ffff88805693d003 R09: 1ffff1100ad27a00
R10: dffffc0000000000 R11: ffffed100ad27a01 R12: 0000000000000001
R13: dffffc0000000000 R14: 00000001000112a2 R15: 00000001000112a4
FS:  0000000000000000(0000) GS:ffff888125f31000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30debff8 CR3: 000000007946a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x525/0x990 net/core/net_namespace.c:252
 cleanup_net+0x4d8/0x7a0 net/core/net_namespace.c:696
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess):
   0:	08 48 89             	or     %cl,-0x77(%rax)
   3:	df e8                	fucomip %st(0),%st
   5:	6d                   	insl   (%dx),%es:(%rdi)
   6:	7b a3                	jnp    0xffffffab
   8:	f8                   	clc
   9:	4c 8b 3b             	mov    (%rbx),%r15
   c:	49 39 df             	cmp    %rbx,%r15
   f:	74 69                	je     0x7a
  11:	e8 90 18 3d f8       	call   0xf83d18a6
  16:	45 31 e4             	xor    %r12d,%r12d
  19:	e9 8e fe ff ff       	jmp    0xfffffeac
  1e:	e8 83 18 3d f8       	call   0xf83d18a6
  23:	48 8d 3d 5c 31 0c 06 	lea    0x60c315c(%rip),%rdi        # 0x60c3186
* 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 cd                	mov    %cs,%ebp
  3e:	fe                   	(bad)
  3f:	ff                   	.byte 0xff

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/12 04:01 linux-next d9771d0dbe18 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/12 03:27 linux-next d9771d0dbe18 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 23:05 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 22:59 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 22:58 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 22:48 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 22:47 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
2025/12/11 05:14 linux-next 5ce74bc1b7cb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nf_conntrack_cleanup_net_list
* Struck through repros no longer work on HEAD.