Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.115' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   27.223909] 
[   27.225549] ======================================================
[   27.231850] WARNING: possible circular locking dependency detected
[   27.238444] 4.14.287-syzkaller #0 Not tainted
[   27.242905] ------------------------------------------------------
[   27.249193] kworker/u4:2/98 is trying to acquire lock:
[   27.254435]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681e02e>] strp_work+0x3e/0x100
[   27.262309] 
[   27.262309] but task is already holding lock:
[   27.268277]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   27.276653] 
[   27.276653] which lock already depends on the new lock.
[   27.276653] 
[   27.284947] 
[   27.284947] the existing dependency chain (in reverse order) is:
[   27.292535] 
[   27.292535] -> #1 ((&strp->work)){+.+.}:
[   27.298050]        flush_work+0xad/0x770
[   27.302081]        __cancel_work_timer+0x321/0x460
[   27.306982]        strp_done+0x53/0xd0
[   27.310839]        kcm_ioctl+0x828/0xfb0
[   27.314883]        sock_ioctl+0x2cc/0x4c0
[   27.319000]        do_vfs_ioctl+0x75a/0xff0
[   27.323293]        SyS_ioctl+0x7f/0xb0
[   27.327152]        do_syscall_64+0x1d5/0x640
[   27.331531]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   27.337208] 
[   27.337208] -> #0 (sk_lock-AF_INET6){+.+.}:
[   27.342985]        lock_acquire+0x170/0x3f0
[   27.347277]        lock_sock_nested+0xb7/0x100
[   27.351830]        strp_work+0x3e/0x100
[   27.355792]        process_one_work+0x793/0x14a0
[   27.360522]        worker_thread+0x5cc/0xff0
[   27.364903]        kthread+0x30d/0x420
[   27.368763]        ret_from_fork+0x24/0x30
[   27.372971] 
[   27.372971] other info that might help us debug this:
[   27.372971] 
[   27.381079]  Possible unsafe locking scenario:
[   27.381079] 
[   27.387103]        CPU0                    CPU1
[   27.391739]        ----                    ----
[   27.396388]   lock((&strp->work));
[   27.399897]                                lock(sk_lock-AF_INET6);
[   27.406186]                                lock((&strp->work));
[   27.412214]   lock(sk_lock-AF_INET6);
[   27.416017] 
[   27.416017]  *** DEADLOCK ***
[   27.416017] 
[   27.422047] 2 locks held by kworker/u4:2/98:
[   27.426424]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   27.435065]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   27.443876] 
[   27.443876] stack backtrace:
[   27.448356] CPU: 1 PID: 98 Comm: kworker/u4:2 Not tainted 4.14.287-syzkaller #0
[   27.455774] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   27.465115] Workqueue: kstrp strp_work
[   27.468974] Call Trace:
[   27.471537]  dump_stack+0x1b2/0x281
[   27.475144]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   27.480915]  __lock_acquire+0x2e0e/0x3f20
[   27.485039]  ? __schedule+0x893/0x1de0
[   27.488901]  ? trace_hardirqs_on+0x10/0x10
[   27.493109]  ? lock_acquire+0x170/0x3f0
[   27.497062]  ? lock_sock_nested+0x98/0x100
[   27.501272]  lock_acquire+0x170/0x3f0
[   27.505046]  ? strp_work+0x3e/0x100
[   27.508646]  lock_sock_nested+0xb7/0x100
[   27.512679]  ? strp_work+0x3e/0x100
[   27.516292]  strp_work+0x3e/0x100
[   27.519724]  process_one_work+0x793/0x14a0
[   27.523931]