[[0;32m OK [0m] Started Getty on tty2.
[[0;32m OK [0m] Reached target Login Prompts.
[[0;32m OK [0m] Started OpenBSD Secure Shell server.
[[0;32m OK [0m] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch.
[[0;32m OK [0m] Reached target Multi-User System.
[[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 Load/Save RF Kill Switch Status.
[[0;32m OK [0m] Started Update UTMP about System Runlevel Changes.
Debian GNU/Linux 9 syzkaller ttyS0
Warning: Permanently added '10.128.0.66' (ECDSA) to the list of known hosts.
executing program
executing program
executing program
executing program
executing program
executing program
syzkaller login: [ 33.088673] hrtimer: interrupt took 34700 ns
executing program
executing program
executing program
executing program
executing program
executing program
[ 33.923311]
[ 33.924944] ============================================
[ 33.930372] WARNING: possible recursive locking detected
[ 33.935904] 4.19.211-syzkaller #0 Not tainted
[ 33.940373] --------------------------------------------
[ 33.945808] swapper/1/0 is trying to acquire lock:
[ 33.950722] 00000000aa437ef3 (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0
[ 33.958167]
[ 33.958167] but task is already holding lock:
[ 33.964206] 00000000aa437ef3 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0
[ 33.973118]
[ 33.973118] other info that might help us debug this:
[ 33.979939] Possible unsafe locking scenario:
[ 33.979939]
[ 33.985975] CPU0
[ 33.988540] ----
[ 33.991103] lock(&port_lock_key);
[ 33.994710] lock(&port_lock_key);
[ 33.998670]
[ 33.998670] *** DEADLOCK ***
[ 33.998670]
[ 34.004706] May be due to missing lock nesting notation
[ 34.004706]
[ 34.011613] 3 locks held by swapper/1/0:
[ 34.015646] #0: 00000000c43b8c65 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240
[ 34.024645] #1: 00000000aa437ef3 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0
[ 34.034004] #2: 000000007a2c7520 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80
[ 34.042581]
[ 34.042581] stack backtrace:
[ 34.047149] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.19.211-syzkaller #0
[ 34.054224] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
[ 34.063567] Call Trace:
[ 34.066132]
[ 34.068264] dump_stack+0x1fc/0x2ef
[ 34.071870] __lock_acquire.cold+0x121/0x57e
[ 34.076262] ? mark_held_locks+0xf0/0xf0
[ 34.080303] ? mark_held_locks+0xf0/0xf0
[ 34.084360] lock_acquire+0x170/0x3c0
[ 34.088163] ? uart_write+0x1ce/0x6f0
[ 34.091955] _raw_spin_lock_irqsave+0x8c/0xc0
[ 34.096436] ? uart_write+0x1ce/0x6f0
[ 34.100225] uart_write+0x1ce/0x6f0
[ 34.103832] ? lock_downgrade+0x720/0x720
[ 34.107967] ? lock_acquire+0x170/0x3c0
[ 34.111921] ? __uart_start.isra.0+0x1c0/0x1c0
[ 34.116484] ? _raw_spin_unlock_irqrestore+0x66/0xe0
[ 34.122786] ? n_hdlc_buf_get+0x1ab/0x240
[ 34.126928] ? __uart_start.isra.0+0x1c0/0x1c0
[ 34.131500] n_hdlc_send_frames+0x278/0x470
[ 34.135824] n_hdlc_tty_wakeup+0xa0/0xc0
[ 34.139883] ? n_hdlc_tty_open+0x510/0x510
[ 34.144103] tty_wakeup+0xd4/0x110
[ 34.147634] tty_port_default_wakeup+0x26/0x40
[ 34.152205] serial8250_tx_chars+0x490/0xaf0
[ 34.156614] serial8250_handle_irq.part.0+0x31f/0x3d0
[ 34.161790] serial8250_default_handle_irq+0xae/0x220
[ 34.166967] serial8250_interrupt+0x101/0x240
[ 34.171443] ? serial8250_backup_timeout+0x4d0/0x4d0
[ 34.176527] __handle_irq_event_percpu+0x27e/0x8e0
[ 34.181436] handle_irq_event+0x102/0x290
[ 34.185563] ? handle_irq_event_percpu+0x160/0x160
[ 34.190473] ? handle_edge_irq+0x29/0xcf0
[ 34.194670] handle_edge_irq+0x260/0xcf0
[ 34.198720] handle_irq+0x35/0x50
[ 34.202157] do_IRQ+0x93/0x1c0
[ 34.205339] common_interrupt+0xf/0xf
[ 34.209136]
[ 34.211358] RIP: 0010:native_safe_halt+0xe/0x10
[ 34.216182] Code: 48 89 df e8 f4 20 7f f9 e9 2e ff ff ff 48 89 df e8 e7 20 7f f9 eb 82 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 14 43 4e 00 fb f4 90 e9 07 00 00 00 0f 00 2d 04 43 4e 00 f4 c3 90 90 41 56 41 55
[ 34.235065] RSP: 0018:ffff8880b5a9fd40 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffd2
[ 34.242772] RAX: 1ffffffff13e3054 RBX: dffffc0000000000 RCX: 0000000000000000
[ 34.250033] RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5a86c44
[ 34.257305] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
[ 34.264559] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89f18290
[ 34.271807] R13: 1ffff11016b53fb2 R14: 0000000000000000 R15: 0000000000000000
[ 34.279068] default_idle+0x49/0x310
[ 34.282850] do_idle+0x2ec/0x4b0
[ 34.286198] ? arch_cpu_idle_exit+0x70/0x70
[ 34.290504] ? _raw_spin_unlock_irqrestore+0x79/0xe0
[ 34.295676] ? lockdep_hardirqs_on+0x3a8/0x5c0
[ 34.300244] cpu_startup_entry+0xc5/0xe0
[ 34.304284] ? cpu_in_idle+0x20/0x20
[ 34.307977] ? _raw_spin_unlock_irqrestore+0x79/0xe0
[ 34.313065] ? lockdep_hardirqs_on+0x3a8/0x5c0
[ 34.317747] start_secondary+0x435/0x5c0
[ 34.321814] ? set_cpu_sibling_map+0x17b0/0x17b0
[ 34.326554] secondary_startup_64+0xa4/0xb0