Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.87' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   26.879953] 
[   26.881593] ======================================================
[   26.887883] WARNING: possible circular locking dependency detected
[   26.894179] 4.14.289-syzkaller #0 Not tainted
[   26.898643] ------------------------------------------------------
[   26.904946] kworker/u4:1/23 is trying to acquire lock:
[   26.910199]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681e12e>] strp_work+0x3e/0x100
[   26.918064] 
[   26.918064] but task is already holding lock:
[   26.924010]  ((&strp->work)){+.+.}, at: [<ffffffff81364ee6>] process_one_work+0x6e6/0x14a0
[   26.932398] 
[   26.932398] which lock already depends on the new lock.
[   26.932398] 
[   26.940700] 
[   26.940700] the existing dependency chain (in reverse order) is:
[   26.948296] 
[   26.948296] -> #1 ((&strp->work)){+.+.}:
[   26.953822]        flush_work+0xad/0x770
[   26.957955]        __cancel_work_timer+0x321/0x460
[   26.962861]        strp_done+0x53/0xd0
[   26.966727]        kcm_ioctl+0x828/0xfb0
[   26.970797]        sock_ioctl+0x2cc/0x4c0
[   26.974924]        do_vfs_ioctl+0x75a/0xff0
[   26.979223]        SyS_ioctl+0x7f/0xb0
[   26.983089]        do_syscall_64+0x1d5/0x640
[   26.987483]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   26.993163] 
[   26.993163] -> #0 (sk_lock-AF_INET6){+.+.}:
[   26.998942]        lock_acquire+0x170/0x3f0
[   27.003248]        lock_sock_nested+0xb7/0x100
[   27.007804]        strp_work+0x3e/0x100
[   27.011751]        process_one_work+0x793/0x14a0
[   27.016480]        worker_thread+0x5cc/0xff0
[   27.020861]        kthread+0x30d/0x420
[   27.024720]        ret_from_fork+0x24/0x30
[   27.028929] 
[   27.028929] other info that might help us debug this:
[   27.028929] 
[   27.037134]  Possible unsafe locking scenario:
[   27.037134] 
[   27.043167]        CPU0                    CPU1
[   27.047808]        ----                    ----
[   27.052447]   lock((&strp->work));
[   27.056053]                                lock(sk_lock-AF_INET6);
[   27.062340]                                lock((&strp->work));
[   27.068368]   lock(sk_lock-AF_INET6);
[   27.072138] 
[   27.072138]  *** DEADLOCK ***
[   27.072138] 
[   27.078166] 2 locks held by kworker/u4:1/23:
[   27.082541]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364eb0>] process_one_work+0x6b0/0x14a0
[   27.091225]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364ee6>] process_one_work+0x6e6/0x14a0
[   27.100138] 
[   27.100138] stack backtrace:
[   27.104610] CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.14.289-syzkaller #0
[   27.112124] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   27.121466] Workqueue: kstrp strp_work
[   27.125333] Call Trace:
[   27.127897]  dump_stack+0x1b2/0x281
[   27.131501]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   27.137271]  __lock_acquire+0x2e0e/0x3f20
[   27.141394]  ? __schedule+0x893/0x1de0
[   27.145257]  ? trace_hardirqs_on+0x10/0x10
[   27.149474]  ? lock_acquire+0x170/0x3f0
[   27.153423]  ? lock_sock_nested+0x98/0x100
[   27.157629]  lock_acquire+0x170/0x3f0
[   27.161402]  ? strp_work+0x3e/0x100
[   27.165009]  lock_sock_nested+0xb7/0x100
[   27.169042]  ? strp_work+0x3e/0x100
[   27.172655]  strp_work+0x3e/0x100
[   27.176101]  process_one_work+0x793/0x14a0
[   27.1803