Re: [syzbot] [wireguard?] WARNING in kthread_unpark (2)

[Hillf Danton]

On Mon, 29 Jul 2024 08:48:30 -0700
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    dc1c8034e31b minmax: simplify min()/max()/clamp() implemen..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=100341c9980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=2258b49cd9b339fa
> dashboard link: https://syzkaller.appspot.com/bug?extid=943d34fa3cf2191e3068
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1022b573980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/6699621c3baa/disk-dc1c8034.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/22380dec726f/vmlinux-dc1c8034.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/04c3f45e6e2d/bzImage-dc1c8034.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+943d34fa3cf2191e3068@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 53 at kernel/kthread.c:525 __kthread_bind_mask kernel/kthread.c:525 [inline]
> WARNING: CPU: 0 PID: 53 at kernel/kthread.c:525 __kthread_bind kernel/kthread.c:538 [inline]
> WARNING: CPU: 0 PID: 53 at kernel/kthread.c:525 kthread_unpark+0x16b/0x210 kernel/kthread.c:631

This warning looks bogus to me since a running workqueue rescuer could not
have a state with TASK_PARKED set.

> Modules linked in:
> CPU: 0 UID: 0 PID: 53 Comm: kworker/u8:3 Not tainted 6.11.0-rc1-syzkaller-00004-gdc1c8034e31b #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
> Workqueue: netns cleanup_net
> 
> RIP: 0010:__kthread_bind_mask kernel/kthread.c:525 [inline]
> RIP: 0010:__kthread_bind kernel/kthread.c:538 [inline]
> RIP: 0010:kthread_unpark+0x16b/0x210 kernel/kthread.c:631
> Code: 00 fc ff df 41 0f b6 04 06 84 c0 0f 85 93 00 00 00 41 80 4d 03 04 4c 89 e7 48 8b 34 24 e8 ad f7 56 0a eb 09 e8 06 a0 33 00 90 <0f> 0b 90 48 89 ef be 08 00 00 00 e8 c5 b5 97 00 f0 80 65 00 fb 4c
> RSP: 0018:ffffc90000bd7760 EFLAGS: 00010293
> 
> RAX: ffffffff815fe27a RBX: 0000000000000000 RCX: ffff888015f90000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffff88801fcd8200 R08: ffffffff815fe207 R09: 1ffffffff269d71e
> R10: dffffc0000000000 R11: fffffbfff269d71f R12: 0000000000000001
> R13: ffff888029c75a2c R14: 1ffff1100538eb45 R15: ffff888029c75a00
> FS:  0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fc23f437d60 CR3: 000000007e72a000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  kthread_stop+0x17a/0x630 kernel/kthread.c:707
>  destroy_workqueue+0x136/0xc40 kernel/workqueue.c:5793
>  wg_destruct+0x1e2/0x2e0 drivers/net/wireguard/device.c:257
>  netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10753
>  default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11889
>  ops_exit_list net/core/net_namespace.c:178 [inline]
>  cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:640
>  process_one_work kernel/workqueue.c:3231 [inline]
>  process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
>  worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
>  kthread+0x2f0/0x390 kernel/kthread.c:389
>  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>  </TASK>