overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
MINIX-fs: bad superblock or unable to read bitmaps
9pnet: Could not find request transport: xen
============================================
WARNING: possible recursive locking detected
4.19.211-syzkaller #0 Not tainted
--------------------------------------------
swapper/1/0 is trying to acquire lock:
0000000026e7febc (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591
but task is already holding lock:
0000000026e7febc (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876
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 swapper/1/0:
#0: 000000008e74f9e0 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline]
#0: 000000008e74f9e0 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115
#1: 0000000026e7febc (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876
#2: 000000008c1a30c4 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_deadlock_bug kernel/locking/lockdep.c:1764 [inline]
check_deadlock kernel/locking/lockdep.c:1808 [inline]
validate_chain kernel/locking/lockdep.c:2404 [inline]
__lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152
uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591
n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403
n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479
tty_wakeup+0xd4/0x110 drivers/tty/tty_io.c:534
tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50
serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1813
serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1900
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1873 [inline]
serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1916
serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125
__handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149
handle_irq_event_percpu kernel/irq/handle.c:189 [inline]
handle_irq_event+0x102/0x290 kernel/irq/handle.c:206
handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800
generic_handle_irq_desc include/linux/irqdesc.h:155 [inline]
handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87
do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246
common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:192
Code: c0 98 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 01 31 d8 01 00 74 25 fb 66 0f 1f 44 00 00 01 00 00 00 e8 26 1b 28 f9 65 8b 05 9f 8d e8 77 85 c0 74 02 5d
RSP: 0018:ffff8880b5a9fc20 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd5
RAX: 1ffffffff13e3053 RBX: ffff8880b5a863c0 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5a86c44
RBP: ffff8880ba12b0c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba12b0c0
R13: ffff88809be54600 R14: 0000000000000000 R15: 0000000000000001
finish_lock_switch kernel/sched/core.c:2578 [inline]
finish_task_switch+0x146/0x760 kernel/sched/core.c:2678
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x88f/0x2040 kernel/sched/core.c:3517
schedule_idle+0x53/0x80 kernel/sched/core.c:3588
do_idle+0x17e/0x4b0 kernel/sched/idle.c:287
cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369
start_secondary+0x435/0x5c0 arch/x86/kernel/smpboot.c:271
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
----------------
Code disassembly (best guess), 5 bytes skipped:
0: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
7: fc ff df
a: 48 c1 e8 03 shr $0x3,%rax
e: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1)
12: 75 31 jne 0x45
14: 48 83 3d 01 31 d8 01 cmpq $0x0,0x1d83101(%rip) # 0x1d8311d
1b: 00
1c: 74 25 je 0x43
1e: fb sti
1f: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
* 25: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction
2a: e8 26 1b 28 f9 callq 0xf9281b55
2f: 65 8b 05 9f 8d e8 77 mov %gs:0x77e88d9f(%rip),%eax # 0x77e88dd5
36: 85 c0 test %eax,%eax
38: 74 02 je 0x3c
3a: 5d pop %rbp