============================================
WARNING: possible recursive locking detected
5.16.0-rc3-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/25353 is trying to acquire lock:
ffffffff90799c10 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577
but task is already holding lock:
ffffffff90799c10 (&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
4 locks held by syz-executor.1/25353:
#0: ffffc9000101cfa0 (&futex_queues[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline]
#0: ffffc9000101cfa0 (&futex_queues[i].lock){+.+.}-{2:2}, at: futex_wake+0x1b5/0x490 kernel/futex/waitwake.c:164
#1: ffff8880767f9430 (&i->lock){-.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline]
#1: ffff8880767f9430 (&i->lock){-.-.}-{2:2}, at: serial8250_interrupt+0x3a/0x200 drivers/tty/serial/8250/8250_core.c:116
#2: ffffffff90799c10 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908
#3: ffff88801df0f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273
stack backtrace:
CPU: 1 PID: 25353 Comm: syz-executor.1 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__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
</IRQ>
<TASK>
asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:200
Code: 81 e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 a4 15 00 00 85 c0 74 2b 8b 82 80 15 00 00 <83> f8 02 75 20 48 8b 8a 88 15 00 00 8b 92 84 15 00 00 48 8b 01 48
RSP: 0018:ffffc90003947c48 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffc9000101cf88 RCX: 0000000000000000
RDX: ffff8880254e6180 RSI: ffffffff816a7f5f RDI: ffffc900032bfcc0
RBP: ffffc900032bfcc0 R08: 0000000000000000 R09: ffff88803102412b
R10: ffffffff816b0fce R11: 0000000000000000 R12: ffffc900032bfcf0
R13: ffffc90003947cf0 R14: ffff888031024128 R15: 00007f09344d6000
plist_node_empty include/linux/plist.h:224 [inline]
__futex_unqueue+0x3f/0x1b0 kernel/futex/core.c:508
futex_wake_mark+0x10f/0x1a0 kernel/futex/waitwake.c:123
futex_wake+0x3b4/0x490 kernel/futex/waitwake.c:177
do_futex+0x25b/0x390 kernel/futex/syscalls.c:127
__do_sys_futex kernel/futex/syscalls.c:199 [inline]
__se_sys_futex kernel/futex/syscalls.c:180 [inline]
__x64_sys_futex+0x1b0/0x4a0 kernel/futex/syscalls.c:180
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: 0033:0x7f09343c3ae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0931939218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f09344d6f68 RCX: 00007f09343c3ae9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f09344d6f6c
RBP: 00007f09344d6f60 R08: 000000000000000e R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 00007f09344d6f6c
R13: 00007ffc2701f32f R14: 00007f0931939300 R15: 0000000000022000
</TASK>
----------------
Code disassembly (best guess):
0: 81 e1 00 01 00 00 and $0x100,%ecx
6: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx
d: 02 00
f: a9 00 01 ff 00 test $0xff0100,%eax
14: 74 0e je 0x24
16: 85 c9 test %ecx,%ecx
18: 74 35 je 0x4f
1a: 8b 82 a4 15 00 00 mov 0x15a4(%rdx),%eax
20: 85 c0 test %eax,%eax
22: 74 2b je 0x4f
24: 8b 82 80 15 00 00 mov 0x1580(%rdx),%eax
* 2a: 83 f8 02 cmp $0x2,%eax <-- trapping instruction
2d: 75 20 jne 0x4f
2f: 48 8b 8a 88 15 00 00 mov 0x1588(%rdx),%rcx
36: 8b 92 84 15 00 00 mov 0x1584(%rdx),%edx
3c: 48 8b 01 mov (%rcx),%rax
3f: 48 rex.W