FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
5.18.0-rc2-syzkaller-00275-g59250f8a7f3a #0 Not tainted
------------------------------------------------------
syz-executor.1/4923 is trying to acquire lock:
ffffffff8bc90400 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1874 [inline]
ffffffff8bc90400 (console_owner){....}-{0:0}, at: vprintk_emit+0x316/0x5f0 kernel/printk/printk.c:2271

but task is already holding lock:
ffff888024440158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xea/0x1e0 drivers/tty/pty.c:120

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&port->lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
       tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:306
       tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:48
       serial8250_tx_chars+0x4f3/0xa50 drivers/tty/serial/8250/8250_port.c:1866
       serial8250_handle_irq.part.0+0x328/0x3d0 drivers/tty/serial/8250/8250_port.c:1953
       serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1926 [inline]
       serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1970
       serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x22b/0x880 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xa7/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:817
       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:636
       native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
       default_idle+0xb/0x10 arch/x86/kernel/process.c:733
       default_idle_call+0x87/0xd0 kernel/sched/idle.c:109
       cpuidle_idle_call kernel/sched/idle.c:191 [inline]
       do_idle+0x401/0x590 kernel/sched/idle.c:303
       cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:400
       start_secondary+0x265/0x340 arch/x86/kernel/smpboot.c:266
       secondary_startup_64_no_verify+0xc3/0xcb

-> #1 (&port_lock_key){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
       serial8250_console_write+0x91a/0xb70 drivers/tty/serial/8250/8250_port.c:3358
       call_console_drivers kernel/printk/printk.c:1952 [inline]
       console_unlock+0x9bc/0xdd0 kernel/printk/printk.c:2774
       vprintk_emit+0x1b4/0x5f0 kernel/printk/printk.c:2272
       vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
       _printk+0xba/0xed kernel/printk/printk.c:2293
       register_console kernel/printk/printk.c:3131 [inline]
       register_console+0x410/0x7c0 kernel/printk/printk.c:3012
       univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:679
       console_init+0x3c1/0x58d kernel/printk/printk.c:3231
       start_kernel+0x30b/0x4a0 init/main.c:1068
       secondary_startup_64_no_verify+0xc3/0xcb

-> #0 (console_owner){....}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3065 [inline]
       check_prevs_add kernel/locking/lockdep.c:3188 [inline]
       validate_chain kernel/locking/lockdep.c:3803 [inline]
       __lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029
       lock_acquire kernel/locking/lockdep.c:5641 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606
       console_trylock_spinning kernel/printk/printk.c:1895 [inline]
       vprintk_emit+0x353/0x5f0 kernel/printk/printk.c:2271
       vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
       _printk+0xba/0xed kernel/printk/printk.c:2293
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail+0x472/0x5a0 lib/fault-inject.c:146
       should_failslab+0x5/0x10 mm/slab_common.c:1313
       slab_pre_alloc_hook mm/slab.h:724 [inline]
       slab_alloc_node mm/slub.c:3131 [inline]
       slab_alloc mm/slub.c:3225 [inline]
       __kmalloc+0x7e/0x350 mm/slub.c:4410
       kmalloc include/linux/slab.h:586 [inline]
       tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:178
       __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
       tty_insert_flip_string_fixed_flag+0x8c/0x240 drivers/tty/tty_buffer.c:321
       tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
       pty_write+0x11c/0x1e0 drivers/tty/pty.c:122
       n_tty_write+0xa7a/0xfc0 drivers/tty/n_tty.c:2271
       do_tty_write drivers/tty/tty_io.c:1024 [inline]
       file_tty_write.constprop.0+0x520/0x900 drivers/tty/tty_io.c:1095
       call_write_iter include/linux/fs.h:2050 [inline]
       new_sync_write+0x38a/0x560 fs/read_write.c:504
       vfs_write+0x7c0/0xac0 fs/read_write.c:591
       ksys_write+0x127/0x250 fs/read_write.c:644
       do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
       __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
       do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
       entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

other info that might help us debug this:

Chain exists of:
  console_owner --> &port_lock_key --> &port->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&port->lock);
                               lock(&port_lock_key);
                               lock(&port->lock);
  lock(console_owner);

 *** DEADLOCK ***

5 locks held by syz-executor.1/4923:
 #0: ffff888023369098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffff888023369130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
 #1: ffff888023369130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:973 [inline]
 #1: ffff888023369130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x299/0x900 drivers/tty/tty_io.c:1095
 #2: ffff8880233692e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1bf/0xfc0 drivers/tty/n_tty.c:2231
 #3: ffffc90007719378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0xa47/0xfc0 drivers/tty/n_tty.c:2270
 #4: ffff888024440158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xea/0x1e0 drivers/tty/pty.c:120

stack backtrace:
CPU: 0 PID: 4923 Comm: syz-executor.1 Not tainted 5.18.0-rc2-syzkaller-00275-g59250f8a7f3a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2145
 check_prev_add kernel/locking/lockdep.c:3065 [inline]
 check_prevs_add kernel/locking/lockdep.c:3188 [inline]
 validate_chain kernel/locking/lockdep.c:3803 [inline]
 __lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029
 lock_acquire kernel/locking/lockdep.c:5641 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606
 console_trylock_spinning kernel/printk/printk.c:1895 [inline]
 vprintk_emit+0x353/0x5f0 kernel/printk/printk.c:2271
 vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
 _printk+0xba/0xed kernel/printk/printk.c:2293
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail+0x472/0x5a0 lib/fault-inject.c:146
 should_failslab+0x5/0x10 mm/slab_common.c:1313
 slab_pre_alloc_hook mm/slab.h:724 [inline]
 slab_alloc_node mm/slub.c:3131 [inline]
 slab_alloc mm/slub.c:3225 [inline]
 __kmalloc+0x7e/0x350 mm/slub.c:4410
 kmalloc include/linux/slab.h:586 [inline]
 tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:178
 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x8c/0x240 drivers/tty/tty_buffer.c:321
 tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
 pty_write+0x11c/0x1e0 drivers/tty/pty.c:122
 n_tty_write+0xa7a/0xfc0 drivers/tty/n_tty.c:2271
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write.constprop.0+0x520/0x900 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write+0x38a/0x560 fs/read_write.c:504
 vfs_write+0x7c0/0xac0 fs/read_write.c:591
 ksys_write+0x127/0x250 fs/read_write.c:644
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f4b549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7f465cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000080
RDX: 000000000000ff2e RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
CPU: 0 PID: 4923 Comm: syz-executor.1 Not tainted 5.18.0-rc2-syzkaller-00275-g59250f8a7f3a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail.cold+0x5/0xa lib/fault-inject.c:146
 should_failslab+0x5/0x10 mm/slab_common.c:1313
 slab_pre_alloc_hook mm/slab.h:724 [inline]
 slab_alloc_node mm/slub.c:3131 [inline]
 slab_alloc mm/slub.c:3225 [inline]
 __kmalloc+0x7e/0x350 mm/slub.c:4410
 kmalloc include/linux/slab.h:586 [inline]
 tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:178
 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x8c/0x240 drivers/tty/tty_buffer.c:321
 tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
 pty_write+0x11c/0x1e0 drivers/tty/pty.c:122
 n_tty_write+0xa7a/0xfc0 drivers/tty/n_tty.c:2271
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write.constprop.0+0x520/0x900 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write+0x38a/0x560 fs/read_write.c:504
 vfs_write+0x7c0/0xac0 fs/read_write.c:591
 ksys_write+0x127/0x250 fs/read_write.c:644
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f4b549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7f465cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000080
RDX: 000000000000ff2e RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	03 74 c0 01          	add    0x1(%rax,%rax,8),%esi
   4:	10 05 03 74 b8 01    	adc    %al,0x1b87403(%rip)        # 0x1b8740d
   a:	10 06                	adc    %al,(%rsi)
   c:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
  10:	10 07                	adc    %al,(%rdi)
  12:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
  16:	10 08                	adc    %cl,(%rax)
  18:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1c:	00 00                	add    %al,(%rax)
  1e:	00 00                	add    %al,(%rax)
  20:	00 51 52             	add    %dl,0x52(%rcx)
  23:	55                   	push   %rbp
  24:	89 e5                	mov    %esp,%ebp
  26:	0f 34                	sysenter
  28:	cd 80                	int    $0x80
* 2a:	5d                   	pop    %rbp <-- trapping instruction
  2b:	5a                   	pop    %rdx
  2c:	59                   	pop    %rcx
  2d:	c3                   	retq
  2e:	90                   	nop
  2f:	90                   	nop
  30:	90                   	nop
  31:	90                   	nop
  32:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  39:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi