[ 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 '10.128.0.151' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.288593] [ 31.290227] ====================================================== [ 31.296620] WARNING: possible circular locking dependency detected [ 31.302910] 4.14.290-syzkaller #0 Not tainted [ 31.307375] ------------------------------------------------------ [ 31.313665] syz-executor282/7976 is trying to acquire lock: [ 31.319346] ((&strp->work)){+.+.}, at: [] flush_work+0x88/0x770 [ 31.327038] [ 31.327038] but task is already holding lock: [ 31.332981] (sk_lock-AF_INET6){+.+.}, at: [] kcm_ioctl+0x328/0xfb0 [ 31.340931] [ 31.340931] which lock already depends on the new lock. [ 31.340931] [ 31.349220] [ 31.349220] the existing dependency chain (in reverse order) is: [ 31.356816] [ 31.356816] -> #1 (sk_lock-AF_INET6){+.+.}: [ 31.362597] lock_sock_nested+0xb7/0x100 [ 31.367152] strp_work+0x3e/0x100 [ 31.371100] process_one_work+0x793/0x14a0 [ 31.375831] worker_thread+0x5cc/0xff0 [ 31.380218] kthread+0x30d/0x420 [ 31.384085] ret_from_fork+0x24/0x30 [ 31.388288] [ 31.388288] -> #0 ((&strp->work)){+.+.}: [ 31.393812] lock_acquire+0x170/0x3f0 [ 31.398123] flush_work+0xad/0x770 [ 31.402160] __cancel_work_timer+0x321/0x460 [ 31.407113] strp_done+0x53/0xd0 [ 31.410976] kcm_ioctl+0x828/0xfb0 [ 31.415014] sock_ioctl+0x2cc/0x4c0 [ 31.419242] do_vfs_ioctl+0x75a/0xff0 [ 31.423543] SyS_ioctl+0x7f/0xb0 [ 31.427411] do_syscall_64+0x1d5/0x640 [ 31.431800] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.437506] [ 31.437506] other info that might help us debug this: [ 31.437506] [ 31.445628] Possible unsafe locking scenario: [ 31.445628] [ 31.451662] CPU0 CPU1 [ 31.456310] ---- ---- [ 31.460950] lock(sk_lock-AF_INET6); [ 31.464727] lock((&strp->work)); [ 31.470765] lock(sk_lock-AF_INET6); [ 31.477056] lock((&strp->work)); [ 31.480571] [ 31.480571] *** DEADLOCK *** [ 31.480571] [ 31.486616] 1 lock held by syz-executor282/7976: [ 31.491342] #0: (sk_lock-AF_INET6){+.+.}, at: [] kcm_ioctl+0x328/0xfb0 [ 31.499726] [ 31.499726] stack backtrace: [ 31.504209] CPU: 0 PID: 7976 Comm: syz-executor282 Not tainted 4.14.290-syzkaller #0 [ 31.512091] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 [ 31.521421] Call Trace: [ 31.523987] dump_stack+0x1b2/0x281 [ 31.527592] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 31.533368] __lock_acquire+0x2e0e/0x3f20 [ 31.537510] ? lock_acquire+0x170/0x3f0 [ 31.541459] ? trace_hardirqs_on+0x10/0x10 [ 31.545677] ? flush_work+0x88/0x770 [ 31.549363] lock_acquire+0x170/0x3f0 [ 31.553140] ? flush_work+0x88/0x770 [ 31.556829] ? flush_work+0x5a7/0x770 [ 31.560601] flush_work+0xad/0x770 [ 31.564116] ? flush_work+0x88/0x770 [ 31.567803] ? debug_object_active_state+0x330/0x330 [ 31.572879] ? worker_thread+0xff0/0xff0 [ 31.576914] ? trace_hardirqs_on+0x10/0x10 [ 31.581218] ? __debug_object_init+0x3fc/0x7a0 [ 31.585791] ? del_timer+0xb3/0xe0 [ 31.589306] ? process_timeout+0x20/0x20 [ 31.593349] ? mark_held_locks+0xa6/0xf0 [ 31.597399] ? __cancel_work_timer+0x2c1/0x460 [ 31.601954] __cancel_work_timer+0x321/0x460 [ 31.606336] ? work_on_cpu_safe+0x70/0x70 [ 31.610475] ? mark_held_locks+0xa6/0xf0 [ 31.614519] ? __local_bh_enable_ip+0xc1/0x170 [ 31.619080] strp_done+0x53/0xd0 [ 31.622435] kcm_ioctl+0x828/0xfb0 [ 31.625950] ? kcm_release+0x700/0x700 [ 31.629818] sock_ioctl+0x2cc/0x4c0 [ 31.633417] ? sock_release+0x1e0/0x1e0 [ 31.637367] do_vfs_ioctl+0x75a/0xff0 [ 31.641143] ? inet_dgram_connect+0x11c/0x1f0 [ 31.645612] ? ioctl_preallocate+0x1a0/0x1a0 [ 31.649991] ? SyS_accept+0x30/0x30 [ 31.653596] ? sock_poll+0x220/0x220 [ 31.657293] ? security_file_ioctl+0x83/0xb0 [ 31.661688] SyS_ioctl+0x7f/0xb0 [ 31.665030] ? do_vfs_ioctl+0xff0/0xff0 [ 31.668977] do_syscall_64+0x1d5/0x640 [ 31.672848] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.678019] RIP: 0033:0x7f06f60d93e9 [ 31.681726] RSP: 002b:00007ffdc3489528 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 31.68941