[ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ 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 '10.128.0.254' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 27.593573] [ 27.595206] ====================================================== [ 27.601495] WARNING: possible circular locking dependency detected [ 27.607789] 4.14.289-syzkaller #0 Not tainted [ 27.612254] ------------------------------------------------------ [ 27.618545] kworker/u4:1/23 is trying to acquire lock: [ 27.623790] (sk_lock-AF_INET6){+.+.}, at: [] strp_work+0x3e/0x100 [ 27.631651] [ 27.631651] but task is already holding lock: [ 27.637591] ((&strp->work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 [ 27.645971] [ 27.645971] which lock already depends on the new lock. [ 27.645971] [ 27.654255] [ 27.654255] the existing dependency chain (in reverse order) is: [ 27.661866] [ 27.661866] -> #1 ((&strp->work)){+.+.}: [ 27.667388] flush_work+0xad/0x770 [ 27.671422] __cancel_work_timer+0x321/0x460 [ 27.676322] strp_done+0x53/0xd0 [ 27.680200] kcm_ioctl+0x828/0xfb0 [ 27.684234] sock_ioctl+0x2cc/0x4c0 [ 27.688358] do_vfs_ioctl+0x75a/0xff0 [ 27.692659] SyS_ioctl+0x7f/0xb0 [ 27.696519] do_syscall_64+0x1d5/0x640 [ 27.700901] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 27.706579] [ 27.706579] -> #0 (sk_lock-AF_INET6){+.+.}: [ 27.712356] lock_acquire+0x170/0x3f0 [ 27.716666] lock_sock_nested+0xb7/0x100 [ 27.721221] strp_work+0x3e/0x100 [ 27.725193] process_one_work+0x793/0x14a0 [ 27.729940] worker_thread+0x5cc/0xff0 [ 27.734319] kthread+0x30d/0x420 [ 27.738195] ret_from_fork+0x24/0x30 [ 27.742398] [ 27.742398] other info that might help us debug this: [ 27.742398] [ 27.750511] Possible unsafe locking scenario: [ 27.750511] [ 27.756539] CPU0 CPU1 [ 27.761179] ---- ---- [ 27.765816] lock((&strp->work)); [ 27.769327] lock(sk_lock-AF_INET6); [ 27.775639] lock((&strp->work)); [ 27.781669] lock(sk_lock-AF_INET6); [ 27.785457] [ 27.785457] *** DEADLOCK *** [ 27.785457] [ 27.791488] 2 locks held by kworker/u4:1/23: [ 27.795866] #0: ("%s""kstrp"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 [ 27.804533] #1: ((&strp->work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 [ 27.813346] [ 27.813346] stack backtrace: [ 27.817840] CPU: 0 PID: 23 Comm: kworker/u4:1 Not tainted 4.14.289-syzkaller #0 [ 27.825272] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 [ 27.834608] Workqueue: kstrp strp_work [ 27.838469] Call Trace: [ 27.841038] dump_stack+0x1b2/0x281 [ 27.845074] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 27.850845] __lock_acquire+0x2e0e/0x3f20 [ 27.854977] ? __schedule+0x893/0x1de0 [ 27.858838] ? trace_hardirqs_on+0x10/0x10 [ 27.863045] ? lock_acquire+0x170/0x3f0 [ 27.866996] ? lock_sock_nested+0x98/0x100 [ 27.871204] lock_acquire+0x170/0x3f0 [ 27.875065] ? strp_work+0x3e/0x100 [ 27.878691] lock_sock_nested+0xb7/0x100 [ 27.882732] ? strp_work+0x3e/0x100 [ 27.886348] strp_work+0x3e/0x100 [ 27.889778] process_one_work+0x793/0x14a0 [ 27.894