[  OK  ] Reached target Graphical Interface.
         Starting Update UTMP about System Runlevel Changes...
         Starting Load/Save RF Kill Switch Status...
[  OK  ] Started Load/Save RF Kill Switch Status.
[  OK  ] Started Update UTMP about System Runlevel Changes.

Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.209' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   31.959299] 
[   31.960941] ======================================================
[   31.967327] WARNING: possible circular locking dependency detected
[   31.973626] 4.14.287-syzkaller #0 Not tainted
[   31.978124] ------------------------------------------------------
[   31.984419] kworker/u4:0/5 is trying to acquire lock:
[   31.989585]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681e02e>] strp_work+0x3e/0x100
[   31.997450] 
[   31.997450] but task is already holding lock:
[   32.003403]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   32.011784] 
[   32.011784] which lock already depends on the new lock.
[   32.011784] 
[   32.020068] 
[   32.020068] the existing dependency chain (in reverse order) is:
[   32.027657] 
[   32.027657] -> #1 ((&strp->work)){+.+.}:
[   32.033177]        flush_work+0xad/0x770
[   32.037211]        __cancel_work_timer+0x321/0x460
[   32.042114]        strp_done+0x53/0xd0
[   32.045982]        kcm_ioctl+0x828/0xfb0
[   32.050028]        sock_ioctl+0x2cc/0x4c0
[   32.054147]        do_vfs_ioctl+0x75a/0xff0
[   32.058637]        SyS_ioctl+0x7f/0xb0
[   32.062509]        do_syscall_64+0x1d5/0x640
[   32.066990]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   32.072790] 
[   32.072790] -> #0 (sk_lock-AF_INET6){+.+.}:
[   32.078575]        lock_acquire+0x170/0x3f0
[   32.082870]        lock_sock_nested+0xb7/0x100
[   32.087438]        strp_work+0x3e/0x100
[   32.091384]        process_one_work+0x793/0x14a0
[   32.096110]        worker_thread+0x5cc/0xff0
[   32.100489]        kthread+0x30d/0x420
[   32.104359]        ret_from_fork+0x24/0x30
[   32.108563] 
[   32.108563] other info that might help us debug this:
[   32.108563] 
[   32.116673]  Possible unsafe locking scenario:
[   32.116673] 
[   32.122698]        CPU0                    CPU1
[   32.127334]        ----                    ----
[   32.131971]   lock((&strp->work));
[   32.135491]                                lock(sk_lock-AF_INET6);
[   32.141781]                                lock((&strp->work));
[   32.147809]   lock(sk_lock-AF_INET6);
[   32.151593] 
[   32.151593]  *** DEADLOCK ***
[   32.151593] 
[   32.157722] 2 locks held by kworker/u4:0/5:
[   32.162011]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   32.170651]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   32.179465] 
[   32.179465] stack backtrace:
[   32.183935] CPU: 1 PID: 5 Comm: kworker/u4:0 Not tainted 4.14.287-syzkaller #0
[   32.191871] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   32.201204] Workqueue: kstrp strp_work
[   32.205075] Call Trace:
[   32.207641]  dump_stack+0x1b2/0x281
[   32.211242]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   32.217052]  __lock_acquire+0x2e0e/0x3f20
[   32.221178]  ? __schedule+0x893/0x1de0
[   32.225043]  ? trace_hardirqs_on+0x10/0x10
[   32.229251]  ? lock_acquire+0x170/0x3f0
[   32.233198]  ? lock_sock_nested+0x98/0x100
[   32.237405]  lock_acquire+0x170/0x3f0
[   32.241181]  ? strp_work+0x3e/0x100
[   32.244782]  lock_sock_nested+0xb7/0x100
[   32.248816]  ? strp_work+0x3e/0x100
[   32.252415]  strp_work+0x3e/0x100
[   32.255839]  process_one_work+0x793/0x14a0
[   32