FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
5.17.0-rc6-syzkaller-00048-g575115360652 #0 Not tainted
------------------------------------------------------
syz-executor.0/16213 is trying to acquire lock:
ffffffff8ba92c80 (console_owner){-...}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1851 [inline]
ffffffff8ba92c80 (console_owner){-...}-{0:0}, at: vprintk_emit+0x29b/0x4f0 kernel/printk/printk.c:2244

but task is already holding lock:
ffff888018f68958 (&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:305
       tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:48
       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+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:820
       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
       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:112
       cpuidle_idle_call kernel/sched/idle.c:194 [inline]
       do_idle+0x401/0x590 kernel/sched/idle.c:306
       cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
       start_secondary+0x265/0x340 arch/x86/kernel/smpboot.c:272
       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:3351
       call_console_drivers kernel/printk/printk.c:1929 [inline]
       console_unlock+0x7a9/0xb70 kernel/printk/printk.c:2711
       vprintk_emit+0x198/0x4f0 kernel/printk/printk.c:2245
       vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
       _printk+0xba/0xed kernel/printk/printk.c:2266
       register_console kernel/printk/printk.c:3064 [inline]
       register_console+0x410/0x7c0 kernel/printk/printk.c:2945
       univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:679
       console_init+0x3c1/0x58d kernel/printk/printk.c:3164
       start_kernel+0x30b/0x49b init/main.c:1067
       secondary_startup_64_no_verify+0xc3/0xcb

-> #0 (
console_owner
){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3063 [inline]
       check_prevs_add kernel/locking/lockdep.c:3186 [inline]
       validate_chain kernel/locking/lockdep.c:3801 [inline]
       __lock_acquire+0x2ad4/0x56c0 kernel/locking/lockdep.c:5027
       lock_acquire kernel/locking/lockdep.c:5639 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604
       console_trylock_spinning kernel/printk/printk.c:1872 [inline]
       vprintk_emit+0x2d8/0x4f0 kernel/printk/printk.c:2244
       vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
       _printk+0xba/0xed kernel/printk/printk.c:2266
       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:1304
       slab_pre_alloc_hook mm/slab.h:707 [inline]
       slab_alloc_node mm/slub.c:3144 [inline]
       slab_alloc mm/slub.c:3238 [inline]
       __kmalloc+0x72/0x450 mm/slub.c:4420
       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+0x93/0x250 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/0xfd0 drivers/tty/n_tty.c:2271
       do_tty_write drivers/tty/tty_io.c:1024 [inline]
       file_tty_write.constprop.0+0x526/0x910 drivers/tty/tty_io.c:1095
       call_write_iter include/linux/fs.h:2074 [inline]
       do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725
       do_iter_write+0x188/0x710 fs/read_write.c:851
       vfs_iter_write+0x70/0xa0 fs/read_write.c:892
       iter_file_splice_write+0x723/0xc70 fs/splice.c:689
       do_splice_from fs/splice.c:767 [inline]
       direct_splice_actor+0x110/0x180 fs/splice.c:936
       splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
       do_splice_direct+0x1b3/0x280 fs/splice.c:979
       do_sendfile+0xaf2/0x1250 fs/read_write.c:1245
       __do_compat_sys_sendfile fs/read_write.c:1331 [inline]
       __se_compat_sys_sendfile fs/read_write.c:1314 [inline]
       __ia32_compat_sys_sendfile+0x1dd/0x220 fs/read_write.c:1314
       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.0/16213:
 #0: ffff8880218cf098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffff8880218cf130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
 #1: ffff8880218cf130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:973 [inline]
 #1: ffff8880218cf130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x29f/0x910 drivers/tty/tty_io.c:1095
 #2: ffff8880218cf2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1bf/0xfd0 drivers/tty/n_tty.c:2231
 #3: ffffc90025063378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0xa47/0xfd0 drivers/tty/n_tty.c:2270
 #4: ffff888018f68958 (&port->lock){-.-.}-{2:2}, at: pty_write+0xea/0x1e0 drivers/tty/pty.c:120

stack backtrace:
CPU: 3 PID: 16213 Comm: syz-executor.0 Not tainted 5.17.0-rc6-syzkaller-00048-g575115360652 #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:2143
 check_prev_add kernel/locking/lockdep.c:3063 [inline]
 check_prevs_add kernel/locking/lockdep.c:3186 [inline]
 validate_chain kernel/locking/lockdep.c:3801 [inline]
 __lock_acquire+0x2ad4/0x56c0 kernel/locking/lockdep.c:5027
 lock_acquire kernel/locking/lockdep.c:5639 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604
 console_trylock_spinning kernel/printk/printk.c:1872 [inline]
 vprintk_emit+0x2d8/0x4f0 kernel/printk/printk.c:2244
 vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
 _printk+0xba/0xed kernel/printk/printk.c:2266
 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:1304
 slab_pre_alloc_hook mm/slab.h:707 [inline]
 slab_alloc_node mm/slub.c:3144 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 __kmalloc+0x72/0x450 mm/slub.c:4420
 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+0x93/0x250 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/0xfd0 drivers/tty/n_tty.c:2271
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write.constprop.0+0x526/0x910 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2074 [inline]
 do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725
 do_iter_write+0x188/0x710 fs/read_write.c:851
 vfs_iter_write+0x70/0xa0 fs/read_write.c:892
 iter_file_splice_write+0x723/0xc70 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x110/0x180 fs/splice.c:936
 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
 do_splice_direct+0x1b3/0x280 fs/splice.c:979
 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245
 __do_compat_sys_sendfile fs/read_write.c:1331 [inline]
 __se_compat_sys_sendfile fs/read_write.c:1314 [inline]
 __ia32_compat_sys_sendfile+0x1dd/0x220 fs/read_write.c:1314
 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: 0023:0xf6ec6549
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:00000000f58c05cc EFLAGS: 00000296 ORIG_RAX: 00000000000000bb
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000080000012 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
CPU: 3 PID: 16213 Comm: syz-executor.0 Not tainted 5.17.0-rc6-syzkaller-00048-g575115360652 #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:1304
 slab_pre_alloc_hook mm/slab.h:707 [inline]
 slab_alloc_node mm/slub.c:3144 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 __kmalloc+0x72/0x450 mm/slub.c:4420
 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+0x93/0x250 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/0xfd0 drivers/tty/n_tty.c:2271
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write.constprop.0+0x526/0x910 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2074 [inline]
 do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725
 do_iter_write+0x188/0x710 fs/read_write.c:851
 vfs_iter_write+0x70/0xa0 fs/read_write.c:892
 iter_file_splice_write+0x723/0xc70 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x110/0x180 fs/splice.c:936
 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
 do_splice_direct+0x1b3/0x280 fs/splice.c:979
 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245
 __do_compat_sys_sendfile fs/read_write.c:1331 [inline]
 __se_compat_sys_sendfile fs/read_write.c:1314 [inline]
 __ia32_compat_sys_sendfile+0x1dd/0x220 fs/read_write.c:1314
 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: 0023:0xf6ec6549
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:00000000f58c05cc EFLAGS: 00000296 ORIG_RAX: 00000000000000bb
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000080000012 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