[  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 '10.128.0.67' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   28.106068] 
[   28.107714] ======================================================
[   28.114001] WARNING: possible circular locking dependency detected
[   28.120299] 4.14.288-syzkaller #0 Not tainted
[   28.124788] ------------------------------------------------------
[   28.131080] kworker/u4:1/23 is trying to acquire lock:
[   28.136333]  (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681dfbe>] strp_work+0x3e/0x100
[   28.144204] 
[   28.144204] but task is already holding lock:
[   28.150164]  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   28.158549] 
[   28.158549] which lock already depends on the new lock.
[   28.158549] 
[   28.166841] 
[   28.166841] the existing dependency chain (in reverse order) is:
[   28.174435] 
[   28.174435] -> #1 ((&strp->work)){+.+.}:
[   28.179969]        flush_work+0xad/0x770
[   28.184015]        __cancel_work_timer+0x321/0x460
[   28.188924]        strp_done+0x53/0xd0
[   28.192783]        kcm_ioctl+0x828/0xfb0
[   28.196817]        sock_ioctl+0x2cc/0x4c0
[   28.200936]        do_vfs_ioctl+0x75a/0xff0
[   28.205233]        SyS_ioctl+0x7f/0xb0
[   28.209095]        do_syscall_64+0x1d5/0x640
[   28.213581]        entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   28.219437] 
[   28.219437] -> #0 (sk_lock-AF_INET6){+.+.}:
[   28.225215]        lock_acquire+0x170/0x3f0
[   28.229524]        lock_sock_nested+0xb7/0x100
[   28.234096]        strp_work+0x3e/0x100
[   28.238042]        process_one_work+0x793/0x14a0
[   28.242774]        worker_thread+0x5cc/0xff0
[   28.247154]        kthread+0x30d/0x420
[   28.251014]        ret_from_fork+0x24/0x30
[   28.255215] 
[   28.255215] other info that might help us debug this:
[   28.255215] 
[   28.263326]  Possible unsafe locking scenario:
[   28.263326] 
[   28.269363]        CPU0                    CPU1
[   28.274002]        ----                    ----
[   28.278638]   lock((&strp->work));
[   28.282150]                                lock(sk_lock-AF_INET6);
[   28.288438]                                lock((&strp->work));
[   28.294476]   lock(sk_lock-AF_INET6);
[   28.298245] 
[   28.298245]  *** DEADLOCK ***
[   28.298245] 
[   28.304280] 2 locks held by kworker/u4:1/23:
[   28.308656]  #0:  ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[   28.317307]  #1:  ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[   28.326121] 
[   28.326121] stack backtrace:
[   28.330589] CPU: 0 PID: 23 Comm: kworker/u4:1 Not tainted 4.14.288-syzkaller #0
[   28.338002] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[   28.347334] Workqueue: kstrp strp_work
[   28.351191] Call Trace:
[   28.353760]  dump_stack+0x1b2/0x281
[   28.357375]  print_circular_bug.constprop.0.cold+0x2d7/0x41e
[   28.363145]  __lock_acquire+0x2e0e/0x3f20
[   28.367266]  ? __schedule+0x893/0x1de0
[   28.371125]  ? trace_hardirqs_on+0x10/0x10
[   28.375335]  ? lock_acquire+0x170/0x3f0
[   28.379283]  ? lock_sock_nested+0x98/0x100
[   28.383493]  lock_acquire+0x170/0x3f0
[   28.387283]  ? strp_work+0x3e/0x100
[   28.390881]  lock_sock_nested+0xb7/0x100
[   28.394913]  ? strp_work+0x3e/0x100
[   28.398511]  strp_work+0x3e/0x100
[   28.401936]  process_one_work+0x793/0x14a0
[   28.406141]  ?