[[0;32m OK [0m] Reached target Graphical Interface.
Starting Update UTMP about System Runlevel Changes...
Starting Load/Save RF Kill Switch Status...
[[0;32m OK [0m] Started Update UTMP about System Runlevel Changes.
[[0;32m OK [0m] Started Load/Save RF Kill Switch Status.
Debian GNU/Linux 9 syzkaller ttyS0
Warning: Permanently added '10.128.0.126' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 31.948789]
[ 31.950398] ============================================
[ 31.955819] WARNING: possible recursive locking detected
[ 31.961240] 4.14.279-syzkaller #0 Not tainted
[ 31.965707] --------------------------------------------
[ 31.971125] swapper/1/0 is trying to acquire lock:
[ 31.976023] (&port_lock_key){-.-.}, at: [<ffffffff835a4ea9>] uart_write+0x109/0x560
[ 31.983883]
[ 31.983883] but task is already holding lock:
[ 31.989823] (&port_lock_key){-.-.}, at: [<ffffffff835c0260>] serial8250_handle_irq.part.0+0x20/0x330
[ 31.999163]
[ 31.999163] other info that might help us debug this:
[ 32.005803] Possible unsafe locking scenario:
[ 32.005803]
[ 32.011834] CPU0
[ 32.014389] ----
[ 32.016943] lock(&port_lock_key);
[ 32.020542] lock(&port_lock_key);
[ 32.024140]
[ 32.024140] *** DEADLOCK ***
[ 32.024140]
[ 32.030174] May be due to missing lock nesting notation
[ 32.030174]
[ 32.037073] 3 locks held by swapper/1/0:
[ 32.041103] #0: (&(&i->lock)->rlock){-.-.}, at: [<ffffffff835ad6ca>] serial8250_interrupt+0x3a/0x210
[ 32.050533] #1: (&port_lock_key){-.-.}, at: [<ffffffff835c0260>] serial8250_handle_irq.part.0+0x20/0x330
[ 32.060306] #2: (&tty->ldisc_sem){++++}, at: [<ffffffff8355257b>] tty_ldisc_ref+0x1b/0x80
[ 32.069131]
[ 32.069131] stack backtrace:
[ 32.073601] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.279-syzkaller #0
[ 32.080667] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 32.089992] Call Trace:
[ 32.092550] <IRQ>
[ 32.094675] dump_stack+0x1b2/0x281
[ 32.098276] __lock_acquire.cold+0x180/0x97c
[ 32.102658] ? __lock_acquire+0x2190/0x3f20
[ 32.106962] ? trace_hardirqs_on+0x10/0x10
[ 32.111173] ? trace_hardirqs_on+0x10/0x10
[ 32.115388] ? trace_hardirqs_on+0x10/0x10
[ 32.119602] lock_acquire+0x170/0x3f0
[ 32.123390] ? uart_write+0x109/0x560
[ 32.127168] _raw_spin_lock_irqsave+0x8c/0xc0
[ 32.131641] ? uart_write+0x109/0x560
[ 32.135420] uart_write+0x109/0x560
[ 32.139020] ? n_hdlc_buf_get+0x194/0x220
[ 32.143144] ? __uart_start.isra.0+0x1b0/0x1b0
[ 32.147702] n_hdlc_send_frames+0x241/0x410
[ 32.151999] n_hdlc_tty_wakeup+0x95/0xb0
[ 32.156036] ? n_hdlc_tty_open+0x4d0/0x4d0
[ 32.160246] tty_wakeup+0xc3/0xf0
[ 32.163672] tty_port_default_wakeup+0x26/0x40
[ 32.168225] serial8250_tx_chars+0x3fe/0xbe0
[ 32.172611] serial8250_handle_irq.part.0+0x28d/0x330
[ 32.177777] serial8250_default_handle_irq+0x8a/0x1f0
[ 32.182939] serial8250_interrupt+0xf3/0x210
[ 32.187321] ? rcu_lockdep_current_cpu_online+0xed/0x140
[ 32.192742] ? serial8250_backup_timeout+0x440/0x440
[ 32.197818] __handle_irq_event_percpu+0xee/0x7f0
[ 32.202633] handle_irq_event+0xf0/0x250
[ 32.206665] ? handle_irq_event_percpu+0x120/0x120
[ 32.211564] handle_edge_irq+0x224/0xc40
[ 32.215599] handle_irq+0x35/0x50
[ 32.219023] do_IRQ+0x93/0x1d0
[ 32.222186] common_interrupt+0x93/0x93
[ 32.226129] </IRQ>
[ 32.228338] RIP: 0010:native_safe_halt+0xe/0x10
[ 32.232979] RSP: 0018:ffff8880b5487e68 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffc8
[ 32.240658] RAX: 1ffffffff11e1314 RBX: dffffc0000000000 RCX: 0000000000000000
[ 32.247901] RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5478bc4
[ 32.255140] RBP: ffffffff88f09890 R08: ffffffff88cc9d68 R09: 0000000000000000
[ 32.262381] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1016a8f068
[ 32.269620] R13: ffff8880b5478340 R14: 0000000000000000 R15: 0000000000000000
[ 32.276866] default_idle+0x47/0x370
[ 32.280551] do_idle+0x250/0x3c0
[ 32.283888] cpu_startup_entry+0x14/0x20
[ 32.287922] start_secondary+0x4db/0x670
[ 32.291960] ? set_cpu_sibling_map+0x1680/0x1680
[ 32.296687] secondary_startup_64+0xa5/0xb0