============================================
WARNING: possible recursive locking detected
5.16.0-rc2-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.4/16136 is trying to acquire lock:
ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577
but task is already holding lock:
ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&port_lock_key);
lock(&port_lock_key);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by syz-executor.4/16136:
#0: ffff88807783beb0 (&i->lock){-.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline]
#0: ffff88807783beb0 (&i->lock){-.-.}-{2:2}, at: serial8250_interrupt+0x3a/0x200 drivers/tty/serial/8250/8250_core.c:116
#1: ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908
#2: ffff888084ae1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273
stack backtrace:
CPU: 0 PID: 16136 Comm: syz-executor.4 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2956 [inline]
check_deadlock kernel/locking/lockdep.c:2999 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027
lock_acquire kernel/locking/lockdep.c:5637 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577
n_hdlc_send_frames+0x24b/0x490 drivers/tty/n_hdlc.c:290
tty_wakeup+0xe1/0x120 drivers/tty/tty_io.c:534
tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:51
serial8250_tx_chars+0x4f3/0xad0 drivers/tty/serial/8250/8250_port.c:1845
serial8250_handle_irq.part.0+0x328/0x3d0 drivers/tty/serial/8250/8250_port.c:1932
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1905 [inline]
serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1949
serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x303/0x8f0 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:198 [inline]
handle_irq_event+0x102/0x280 kernel/irq/handle.c:215
handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:822
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:231 [inline]
__common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250
common_interrupt+0xa4/0xc0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194
Code: 74 24 10 e8 2a f0 15 f8 48 89 ef e8 72 66 16 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 33 30 09 f8 65 8b 05 1c b3 bb 76 85 c0 74 0a 5b 5d c3 e8 10 20
RSP: 0018:ffffc9000286fc78 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff1b21ed1
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff888018cb3620 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff817ddd38 R11: 0000000000000000 R12: dffffc0000000000
R13: 00007ffea1d1888c R14: 0000000000000004 R15: 0000000000000000
do_wait+0x150/0xce0 kernel/exit.c:1497
kernel_wait4+0x14c/0x260 kernel/exit.c:1684
__do_sys_wait4+0x13f/0x150 kernel/exit.c:1712
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f356be81f87
Code: 89 7c 24 10 48 89 4c 24 18 e8 35 50 02 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 65 50 02 00 8b 44
RSP: 002b:00007ffea1d18800 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 00000000000001b6 RCX: 00007f356be81f87
RDX: 0000000040000001 RSI: 00007ffea1d1888c RDI: 00000000ffffffff
RBP: 00007ffea1d1888c R08: 0000000000000000 R09: 00007ffea1dbe080
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 0000000000094494 R14: 0000000000000013 R15: 00007ffea1d188f0
----------------
Code disassembly (best guess):
0: 74 24 je 0x26
2: 10 e8 adc %ch,%al
4: 2a f0 sub %al,%dh
6: 15 f8 48 89 ef adc $0xef8948f8,%eax
b: e8 72 66 16 f8 callq 0xf8166682
10: 81 e3 00 02 00 00 and $0x200,%ebx
16: 75 25 jne 0x3d
18: 9c pushfq
19: 58 pop %rax
1a: f6 c4 02 test $0x2,%ah
1d: 75 2d jne 0x4c
1f: 48 85 db test %rbx,%rbx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 33 30 09 f8 callq 0xf8093062 <-- trapping instruction
2f: 65 8b 05 1c b3 bb 76 mov %gs:0x76bbb31c(%rip),%eax # 0x76bbb352
36: 85 c0 test %eax,%eax
38: 74 0a je 0x44
3a: 5b pop %rbx
3b: 5d pop %rbp
3c: c3 retq
3d: e8 .byte 0xe8
3e: 10 20 adc %ah,(%rax)