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

Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.61' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   31.382057] 
[   31.383697] ======================================================
[   31.389987] WARNING: possible circular locking dependency detected
[   31.396277] 4.14.284-syzkaller #0 Not tainted
[   31.400739] ------------------------------------------------------
[   31.407024] kworker/u4:0/5 is trying to acquire lock:
[   31.412181]  (sk_lock-AF_INET){+.+.}, at: [<ffffffff86826dde>] strp_work+0x3e/0x100
[   31.419955] 
[   31.419955] but task is already holding lock:
[   31.425901]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   31.434292] 
[   31.434292] which lock already depends on the new lock.
[   31.434292] 
[   31.442581] 
[   31.442581] the existing dependency chain (in reverse order) is:
[   31.450179] 
[   31.450179] -> #1 ((&strp->work)){+.+.}:
[   31.455703]        flush_work+0xad/0x770
[   31.459735]        __cancel_work_timer+0x321/0x460
[   31.464636]        strp_done+0x53/0xd0
[   31.468507]        kcm_ioctl+0x828/0xfb0
[   31.472538]        sock_ioctl+0x2cc/0x4c0
[   31.476660]        do_vfs_ioctl+0x75a/0xff0
[   31.480955]        SyS_ioctl+0x7f/0xb0
[   31.484813]        do_syscall_64+0x1d5/0x640
[   31.489190]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   31.494870] 
[   31.494870] -> #0 (sk_lock-AF_INET){+.+.}:
[   31.500557]        lock_acquire+0x170/0x3f0
[   31.504862]        lock_sock_nested+0xb7/0x100
[   31.509414]        strp_work+0x3e/0x100
[   31.513361]        process_one_work+0x793/0x14a0
[   31.518086]        worker_thread+0x5cc/0xff0
[   31.522466]        kthread+0x30d/0x420
[   31.526327]        ret_from_fork+0x24/0x30
[   31.530527] 
[   31.530527] other info that might help us debug this:
[   31.530527] 
[   31.538637]  Possible unsafe locking scenario:
[   31.538637] 
[   31.544662]        CPU0                    CPU1
[   31.549298]        ----                    ----
[   31.553935]   lock((&strp->work));
[   31.557446]                                lock(sk_lock-AF_INET);
[   31.563648]                                lock((&strp->work));
[   31.569677]   lock(sk_lock-AF_INET);
[   31.573360] 
[   31.573360]  *** DEADLOCK ***
[   31.573360] 
[   31.579401] 2 locks held by kworker/u4:0/5:
[   31.583704]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   31.592358]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   31.601181] 
[   31.601181] stack backtrace:
[   31.605667] CPU: 0 PID: 5 Comm: kworker/u4:0 Not tainted 4.14.284-syzkaller #0
[   31.613171] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   31.622505] Workqueue: kstrp strp_work
[   31.626360] Call Trace:
[   31.628931]  dump_stack+0x1b2/0x281
[   31.632532]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   31.638302]  __lock_acquire+0x2e0e/0x3f20
[   31.642422]  ? trace_hardirqs_on+0x10/0x10
[   31.646629]  ? trace_hardirqs_on+0x10/0x10
[   31.650835]  ? lock_acquire+0x170/0x3f0
[   31.654784]  ? check_preemption_disabled+0x35/0x240
[   31.659786]  ? lock_sock_nested+0x98/0x100
[   31.669060]  lock_acquire+0x170/0x3f0
[   31.672835]  ? strp_work+0x3e/0x100
[   31.676436]  lock_sock_nested+0xb7/0x100
[   31.680468]  ? strp_work+0x3e/