[  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 '10.128.1.22' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   29.469119] 
[   29.470773] ======================================================
[   29.477063] WARNING: possible circular locking dependency detected
[   29.483354] 4.14.287-syzkaller #0 Not tainted
[   29.487820] ------------------------------------------------------
[   29.494106] kworker/u4:4/2850 is trying to acquire lock:
[   29.499530]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681e02e>] strp_work+0x3e/0x100
[   29.507398] 
[   29.507398] but task is already holding lock:
[   29.513339]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   29.521736] 
[   29.521736] which lock already depends on the new lock.
[   29.521736] 
[   29.530059] 
[   29.530059] the existing dependency chain (in reverse order) is:
[   29.537765] 
[   29.537765] -> #1 ((&strp->work)){+.+.}:
[   29.543295]        flush_work+0xad/0x770
[   29.547348]        __cancel_work_timer+0x321/0x460
[   29.552253]        strp_done+0x53/0xd0
[   29.556114]        kcm_ioctl+0x828/0xfb0
[   29.560149]        sock_ioctl+0x2cc/0x4c0
[   29.564418]        do_vfs_ioctl+0x75a/0xff0
[   29.568724]        SyS_ioctl+0x7f/0xb0
[   29.572595]        do_syscall_64+0x1d5/0x640
[   29.576983]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   29.582682] 
[   29.582682] -> #0 (sk_lock-AF_INET6){+.+.}:
[   29.588512]        lock_acquire+0x170/0x3f0
[   29.592821]        lock_sock_nested+0xb7/0x100
[   29.597385]        strp_work+0x3e/0x100
[   29.601340]        process_one_work+0x793/0x14a0
[   29.606071]        worker_thread+0x5cc/0xff0
[   29.610488]        kthread+0x30d/0x420
[   29.614357]        ret_from_fork+0x24/0x30
[   29.618566] 
[   29.618566] other info that might help us debug this:
[   29.618566] 
[   29.626689]  Possible unsafe locking scenario:
[   29.626689] 
[   29.632722]        CPU0                    CPU1
[   29.637363]        ----                    ----
[   29.642003]   lock((&strp->work));
[   29.645517]                                lock(sk_lock-AF_INET6);
[   29.651847]                                lock((&strp->work));
[   29.657875]   lock(sk_lock-AF_INET6);
[   29.661653] 
[   29.661653]  *** DEADLOCK ***
[   29.661653] 
[   29.667713] 2 locks held by kworker/u4:4/2850:
[   29.672263]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   29.681013]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   29.689840] 
[   29.689840] stack backtrace:
[   29.694326] CPU: 1 PID: 2850 Comm: kworker/u4:4 Not tainted 4.14.287-syzkaller #0
[   29.701946] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   29.711294] Workqueue: kstrp strp_work
[   29.715158] Call Trace:
[   29.717726]  dump_stack+0x1b2/0x281
[   29.721331]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   29.727108]  __lock_acquire+0x2e0e/0x3f20
[   29.731235]  ? __schedule+0x893/0x1de0
[   29.735096]  ? trace_hardirqs_on+0x10/0x10
[   29.739318]  ? lock_acquire+0x170/0x3f0
[   29.743267]  ? lock_sock_nested+0x98/0x100
[   29.747478]  lock_acquire+0x170/0x3f0
[   29.751252]  ? strp_work+0x3e/0x100
[   29.754853]  lock_sock_nested+0xb7/0x100
[   29.758904]  ? strp_work+0x3e/0x100
[   29.762505]  strp_work+0x3e/0x100
[   29.765935]  process_one_work+0x793/0x14a0
[