Re: [syzbot] [net?] WARNING in xfrm_state_fini (3)

[Steffen Klassert <steffen.klassert@secunet.com>]

On Tue, Jul 29, 2025 at 12:08:31AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    038d61fd6422 Linux 6.16
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11b88cf0580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=4066f1c76cfbc4fe
> dashboard link: https://syzkaller.appspot.com/bug?extid=6641a61fe0e2e89ae8c5
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16ca1782580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140194a2580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/6505c612be11/disk-038d61fd.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/e466ef29c1ca/vmlinux-038d61fd.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/b6d3d8fc5cbb/bzImage-038d61fd.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 36 at net/xfrm/xfrm_state.c:3284 xfrm_state_fini+0x270/0x2f0 net/xfrm/xfrm_state.c:3284
> Modules linked in:
> CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
> Workqueue: netns cleanup_net
> RIP: 0010:xfrm_state_fini+0x270/0x2f0 net/xfrm/xfrm_state.c:3284
> Code: c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 68 fa 0b f8 48 8b 3b 5b 41 5c 41 5d 41 5e 41 5f 5d e9 56 c8 ec f7 e8 51 e8 a9 f7 90 <0f> 0b 90 e9 fd fd ff ff e8 43 e8 a9 f7 90 0f 0b 90 e9 60 fe ff ff
> RSP: 0018:ffffc90000ac7898 EFLAGS: 00010293
> RAX: ffffffff8a163e8f RBX: ffff888034008000 RCX: ffff888143299e00
> RDX: 0000000000000000 RSI: ffffffff8db8419f RDI: ffff888143299e00
> RBP: ffffc90000ac79b0 R08: ffffffff8f6196e7 R09: 1ffffffff1ec32dc
> R10: dffffc0000000000 R11: fffffbfff1ec32dd R12: ffffffff8f617760
> R13: 1ffff92000158f40 R14: ffff8880340094c0 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff888125d23000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fbd9e960960 CR3: 00000000316d3000 CR4: 0000000000350ef0
> Call Trace:
>  <TASK>
>  xfrm_net_exit+0x2d/0x70 net/xfrm/xfrm_policy.c:4348
>  ops_exit_list net/core/net_namespace.c:200 [inline]
>  ops_undo_list+0x49a/0x990 net/core/net_namespace.c:253
>  cleanup_net+0x4c5/0x800 net/core/net_namespace.c:686
>  process_one_work kernel/workqueue.c:3238 [inline]
>  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
>  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
>  kthread+0x711/0x8a0 kernel/kthread.c:464
>  ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>

Hi Sabrina, your recent ipcomp patches seem to trigger this issue.
At least reverting them make it go away. Can you please look
into this?

Please note that

CONFIG_INET_DIAG_DESTROY=y

has to be set to trigger the warining.

Thanks!