[[0;32m OK [0m] Started Getty on tty3.
[[0;32m OK [0m] Started Getty on tty2.
[[0;32m OK [0m] Started Serial Getty on ttyS0.
[[0;32m OK [0m] Reached target Login Prompts.
[[0;32m OK [0m] Reached target Multi-User System.
[[0;32m OK [0m] Reached target Graphical Interface.
Starting Update UTMP about System Runlevel Changes...
[[0;32m OK [0m] Started Update UTMP about System Runlevel Changes.
Starting Load/Save RF Kill Switch Status...
[[0;32m OK [0m] Started Load/Save RF Kill Switch Status.
Debian GNU/Linux 9 syzkaller ttyS0
Warning: Permanently added '10.128.0.75' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 27.732190]
[ 27.733853] ======================================================
[ 27.740180] WARNING: possible circular locking dependency detected
[ 27.746481] 4.14.288-syzkaller #0 Not tainted
[ 27.750962] ------------------------------------------------------
[ 27.757256] kworker/u4:0/5 is trying to acquire lock:
[ 27.762430] (sk_lock-AF_INET6){+.+.}, at: [<ffffffff8681dfbe>] strp_work+0x3e/0x100
[ 27.770337]
[ 27.770337] but task is already holding lock:
[ 27.776284] ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[ 27.784665]
[ 27.784665] which lock already depends on the new lock.
[ 27.784665]
[ 27.792951]
[ 27.792951] the existing dependency chain (in reverse order) is:
[ 27.800566]
[ 27.800566] -> #1 ((&strp->work)){+.+.}:
[ 27.806096] flush_work+0xad/0x770
[ 27.810133] __cancel_work_timer+0x321/0x460
[ 27.815048] strp_done+0x53/0xd0
[ 27.818927] kcm_ioctl+0x828/0xfb0
[ 27.822968] sock_ioctl+0x2cc/0x4c0
[ 27.827106] do_vfs_ioctl+0x75a/0xff0
[ 27.831409] SyS_ioctl+0x7f/0xb0
[ 27.835404] do_syscall_64+0x1d5/0x640
[ 27.839884] entry_SYSCALL_64_after_hwframe+0x46/0xbb
[ 27.845572]
[ 27.845572] -> #0 (sk_lock-AF_INET6){+.+.}:
[ 27.851355] lock_acquire+0x170/0x3f0
[ 27.855670] lock_sock_nested+0xb7/0x100
[ 27.860232] strp_work+0x3e/0x100
[ 27.864183] process_one_work+0x793/0x14a0
[ 27.868912] worker_thread+0x5cc/0xff0
[ 27.873291] kthread+0x30d/0x420
[ 27.877155] ret_from_fork+0x24/0x30
[ 27.881366]
[ 27.881366] other info that might help us debug this:
[ 27.881366]
[ 27.889498] Possible unsafe locking scenario:
[ 27.889498]
[ 27.895540] CPU0 CPU1
[ 27.900177] ---- ----
[ 27.904827] lock((&strp->work));
[ 27.908339] lock(sk_lock-AF_INET6);
[ 27.914627] lock((&strp->work));
[ 27.920660] lock(sk_lock-AF_INET6);
[ 27.924435]
[ 27.924435] *** DEADLOCK ***
[ 27.924435]
[ 27.930467] 2 locks held by kworker/u4:0/5:
[ 27.934759] #0: ("%s""kstrp"){+.+.}, at: [<ffffffff81364ef0>] process_one_work+0x6b0/0x14a0
[ 27.943582] #1: ((&strp->work)){+.+.}, at: [<ffffffff81364f26>] process_one_work+0x6e6/0x14a0
[ 27.952398]
[ 27.952398] stack backtrace:
[ 27.956881] CPU: 0 PID: 5 Comm: kworker/u4:0 Not tainted 4.14.288-syzkaller #0
[ 27.964210] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[ 27.973547] Workqueue: kstrp strp_work
[ 27.977843] Call Trace:
[ 27.980407] dump_stack+0x1b2/0x281
[ 27.984134] print_circular_bug.constprop.0.cold+0x2d7/0x41e
[ 27.989926] __lock_acquire+0x2e0e/0x3f20
[ 27.994054] ? __schedule+0x893/0x1de0
[ 27.997923] ? trace_hardirqs_on+0x10/0x10
[ 28.002146] ? lock_acquire+0x170/0x3f0
[ 28.006104] ? lock_sock_nested+0x98/0x100
[ 28.010324] lock_acquire+0x170/0x3f0
[ 28.014101] ? strp_work+0x3e/0x100
[ 28.017709] lock_sock_nested+0xb7/0x100
[ 28.021744] ? strp_work+0x3e/0x100
[ 28.025345] strp_work+0x3e/0x100
[ 28.028773] process_one_work+0x793/0x14a0
[ 28.