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

Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.1.33' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   27.891753] 
[   27.893389] ======================================================
[   27.899694] WARNING: possible circular locking dependency detected
[   27.905983] 4.14.288-syzkaller #0 Not tainted
[   27.910445] ------------------------------------------------------
[   27.916732] kworker/u4:1/23 is trying to acquire lock:
[   27.921974]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681dfbe>] strp_work+0x3e/0x100
[   27.929837] 
[   27.929837] but task is already holding lock:
[   27.935779]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   27.944157] 
[   27.944157] which lock already depends on the new lock.
[   27.944157] 
[   27.952439] 
[   27.952439] the existing dependency chain (in reverse order) is:
[   27.960027] 
[   27.960027] -> #1 ((&strp->work)){+.+.}:
[   27.965545]        flush_work+0xad/0x770
[   27.969578]        __cancel_work_timer+0x321/0x460
[   27.974490]        strp_done+0x53/0xd0
[   27.978371]        kcm_ioctl+0x828/0xfb0
[   27.982405]        sock_ioctl+0x2cc/0x4c0
[   27.986523]        do_vfs_ioctl+0x75a/0xff0
[   27.990814]        SyS_ioctl+0x7f/0xb0
[   27.994674]        do_syscall_64+0x1d5/0x640
[   27.999055]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   28.004747] 
[   28.004747] -> #0 (sk_lock-AF_INET6){+.+.}:
[   28.010528]        lock_acquire+0x170/0x3f0
[   28.014818]        lock_sock_nested+0xb7/0x100
[   28.019392]        strp_work+0x3e/0x100
[   28.023336]        process_one_work+0x793/0x14a0
[   28.028066]        worker_thread+0x5cc/0xff0
[   28.032445]        kthread+0x30d/0x420
[   28.036302]        ret_from_fork+0x24/0x30
[   28.040504] 
[   28.040504] other info that might help us debug this:
[   28.040504] 
[   28.048625]  Possible unsafe locking scenario:
[   28.048625] 
[   28.054649]        CPU0                    CPU1
[   28.059283]        ----                    ----
[   28.063921]   lock((&strp->work));
[   28.067432]                                lock(sk_lock-AF_INET6);
[   28.073719]                                lock((&strp->work));
[   28.079745]   lock(sk_lock-AF_INET6);
[   28.083514] 
[   28.083514]  *** DEADLOCK ***
[   28.083514] 
[   28.089541] 2 locks held by kworker/u4:1/23:
[   28.093917]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   28.102642]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   28.111541] 
[   28.111541] stack backtrace:
[   28.116096] CPU: 0 PID: 23 Comm: kworker/u4:1 Not tainted 4.14.288-syzkaller #0
[   28.123510] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   28.132867] Workqueue: kstrp strp_work
[   28.136749] Call Trace:
[   28.139313]  dump_stack+0x1b2/0x281
[   28.142921]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   28.148695]  __lock_acquire+0x2e0e/0x3f20
[   28.152823]  ? __schedule+0x893/0x1de0
[   28.156690]  ? trace_hardirqs_on+0x10/0x10
[   28.160894]  ? lock_acquire+0x170/0x3f0
[   28.164857]  ? lock_sock_nested+0x98/0x100
[   28.169075]  lock_acquire+0x170/0x3f0
[   28.172853]  ? strp_work+0x3e/0x100
[   28.176454]  lock_sock_nested+0xb7/0x100
[   28.180496]  ? strp_work+0x3e/0x100
[   28.184095]  strp_work+0x3e/0x100
[   28.187520]  process_one_work+0x793/0x14a0
[   28.191727]  ?