[  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 '10.128.0.252' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   31.879075] 
[   31.880707] ======================================================
[   31.886995] WARNING: possible circular locking dependency detected
[   31.893316] 4.14.289-syzkaller #0 Not tainted
[   31.897777] ------------------------------------------------------
[   31.904068] kworker/u4:1/23 is trying to acquire lock:
[   31.909327]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681e12e>] strp_work+0x3e/0x100
[   31.917208] 
[   31.917208] but task is already holding lock:
[   31.923149]  ((&strp->work)){+.+.}, at: [<ffffffff81364ee6>] process_one_work+0x6e6/0x14a0
[   31.931537] 
[   31.931537] which lock already depends on the new lock.
[   31.931537] 
[   31.939906] 
[   31.939906] the existing dependency chain (in reverse order) is:
[   31.947523] 
[   31.947523] -> #1 ((&strp->work)){+.+.}:
[   31.953038]        flush_work+0xad/0x770
[   31.957070]        __cancel_work_timer+0x321/0x460
[   31.961968]        strp_done+0x53/0xd0
[   31.965826]        kcm_ioctl+0x828/0xfb0
[   31.969860]        sock_ioctl+0x2cc/0x4c0
[   31.973977]        do_vfs_ioctl+0x75a/0xff0
[   31.978272]        SyS_ioctl+0x7f/0xb0
[   31.982146]        do_syscall_64+0x1d5/0x640
[   31.986524]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   31.992203] 
[   31.992203] -> #0 (sk_lock-AF_INET6){+.+.}:
[   31.997977]        lock_acquire+0x170/0x3f0
[   32.002271]        lock_sock_nested+0xb7/0x100
[   32.006823]        strp_work+0x3e/0x100
[   32.010769]        process_one_work+0x793/0x14a0
[   32.015494]        worker_thread+0x5cc/0xff0
[   32.019871]        kthread+0x30d/0x420
[   32.023734]        ret_from_fork+0x24/0x30
[   32.027949] 
[   32.027949] other info that might help us debug this:
[   32.027949] 
[   32.036059]  Possible unsafe locking scenario:
[   32.036059] 
[   32.042084]        CPU0                    CPU1
[   32.046718]        ----                    ----
[   32.051367]   lock((&strp->work));
[   32.054891]                                lock(sk_lock-AF_INET6);
[   32.061179]                                lock((&strp->work));
[   32.067205]   lock(sk_lock-AF_INET6);
[   32.070974] 
[   32.070974]  *** DEADLOCK ***
[   32.070974] 
[   32.077003] 2 locks held by kworker/u4:1/23:
[   32.081378]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364eb0>] process_one_work+0x6b0/0x14a0
[   32.090018]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364ee6>] process_one_work+0x6e6/0x14a0
[   32.098834] 
[   32.098834] stack backtrace:
[   32.103303] CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.14.289-syzkaller #0
[   32.110715] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   32.120048] Workqueue: kstrp strp_work
[   32.123909] Call Trace:
[   32.126488]  dump_stack+0x1b2/0x281
[   32.130088]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   32.135878]  __lock_acquire+0x2e0e/0x3f20
[   32.140000]  ? __schedule+0x893/0x1de0
[   32.143856]  ? trace_hardirqs_on+0x10/0x10
[   32.148061]  ? lock_acquire+0x170/0x3f0
[   32.152015]  ? lock_sock_nested+0x98/0x100
[   32.156223]  lock_acquire+0x170/0x3f0
[   32.159993]  ? strp_work+0x3e/0x100
[   32.163607]  lock_sock_nested+0xb7/0x100
[   32.167650]  ? strp_work+0x3e/0x100
[   32.171255]  strp_work+0x3e/0x100
[   32.174679]  process_one_work+0x793/0x14a0
[   32.178883]  ?