[  OK  ] Started Getty on tty1.
[  OK  ] Reached target Login Prompts.
[  OK  ] Started OpenBSD Secure Shell server.
[  OK  ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch.
[  OK  ] Reached target Multi-User System.
[  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 '10.128.1.98' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   26.317283] 
[   26.318913] ======================================================
[   26.325209] WARNING: possible circular locking dependency detected
[   26.331521] 4.14.288-syzkaller #0 Not tainted
[   26.336254] ------------------------------------------------------
[   26.342555] kworker/u4:3/256 is trying to acquire lock:
[   26.347886]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681dfbe>] strp_work+0x3e/0x100
[   26.355747] 
[   26.355747] but task is already holding lock:
[   26.361688]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   26.370075] 
[   26.370075] which lock already depends on the new lock.
[   26.370075] 
[   26.378360] 
[   26.378360] the existing dependency chain (in reverse order) is:
[   26.385947] 
[   26.385947] -> #1 ((&strp->work)){+.+.}:
[   26.391463]        flush_work+0xad/0x770
[   26.395496]        __cancel_work_timer+0x321/0x460
[   26.400402]        strp_done+0x53/0xd0
[   26.404261]        kcm_ioctl+0x828/0xfb0
[   26.408294]        sock_ioctl+0x2cc/0x4c0
[   26.412414]        do_vfs_ioctl+0x75a/0xff0
[   26.416710]        SyS_ioctl+0x7f/0xb0
[   26.420569]        do_syscall_64+0x1d5/0x640
[   26.424949]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   26.430626] 
[   26.430626] -> #0 (sk_lock-AF_INET6){+.+.}:
[   26.436404]        lock_acquire+0x170/0x3f0
[   26.440709]        lock_sock_nested+0xb7/0x100
[   26.445262]        strp_work+0x3e/0x100
[   26.449209]        process_one_work+0x793/0x14a0
[   26.453946]        worker_thread+0x5cc/0xff0
[   26.458340]        kthread+0x30d/0x420
[   26.462207]        ret_from_fork+0x24/0x30
[   26.466409] 
[   26.466409] other info that might help us debug this:
[   26.466409] 
[   26.474521]  Possible unsafe locking scenario:
[   26.474521] 
[   26.480547]        CPU0                    CPU1
[   26.485183]        ----                    ----
[   26.489818]   lock((&strp->work));
[   26.493329]                                lock(sk_lock-AF_INET6);
[   26.499628]                                lock((&strp->work));
[   26.505654]   lock(sk_lock-AF_INET6);
[   26.509424] 
[   26.509424]  *** DEADLOCK ***
[   26.509424] 
[   26.515468] 2 locks held by kworker/u4:3/256:
[   26.519928]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   26.528576]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   26.537396] 
[   26.537396] stack backtrace:
[   26.541867] CPU: 0 PID: 256 Comm: kworker/u4:3 Not tainted 4.14.288-syzkaller #0
[   26.549379] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   26.558719] Workqueue: kstrp strp_work
[   26.562588] Call Trace:
[   26.565151]  dump_stack+0x1b2/0x281
[   26.568753]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   26.574525]  __lock_acquire+0x2e0e/0x3f20
[   26.578649]  ? __schedule+0x893/0x1de0
[   26.582511]  ? trace_hardirqs_on+0x10/0x10
[   26.586718]  ? lock_acquire+0x170/0x3f0
[   26.590667]  ? lock_sock_nested+0x98/0x100
[   26.594879]  lock_acquire+0x170/0x3f0
[   26.598657]  ? strp_work+0x3e/0x100
[   26.602261]  lock_sock_nested+0xb7/0x100
[   26.606291]  ? strp_work+0x3e/0x100
[   26.609889]  strp_work+0x3e/0x100
[   26.613315]  process_one_work+0x793/0x14a0
[   26.61753