FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
5.17.0-rc5-syzkaller-00006-g917bbdb107f8 #0 Not tainted
------------------------------------------------------
syz-executor.4/29521 is trying to acquire lock:
ffffffff8cb11800 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x2d/0x60 kernel/printk/printk.c:1778

but task is already holding lock:
ffff8880736f6158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc5/0x170 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}:
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5639
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       tty_port_tty_get+0x21/0xe0 drivers/tty/tty_port.c:305
       tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:48
       serial8250_tx_chars+0x68e/0x8a0 drivers/tty/serial/8250/8250_port.c:1845
       serial8250_handle_irq+0x2fd/0x3e0 drivers/tty/serial/8250/8250_port.c:1932
       serial8250_default_handle_irq+0xaf/0x190 drivers/tty/serial/8250/8250_port.c:1949
       serial8250_interrupt+0xa3/0x1e0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x1f7/0x660 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x83/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x245/0xbe0 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+0xce/0x1e0 arch/x86/kernel/irq.c:250
       common_interrupt+0x4a/0xc0 arch/x86/kernel/irq.c:240
       asm_common_interrupt+0x1e/0x40
       ffs arch/x86/include/asm/bitops.h:297 [inline]
       __do_softirq+0x1e3/0x7a3 kernel/softirq.c:546
       __irq_exit_rcu+0xec/0x170 kernel/softirq.c:637
       irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
       sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1097
       asm_sysvec_apic_timer_interrupt+0x12/0x20
       native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
       acpi_safe_halt drivers/acpi/processor_idle.c:115 [inline]
       acpi_idle_do_entry drivers/acpi/processor_idle.c:556 [inline]
       acpi_idle_enter+0x42d/0x790 drivers/acpi/processor_idle.c:692
       cpuidle_enter_state+0x507/0xea0 drivers/cpuidle/cpuidle.c:237
       cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351
       call_cpuidle kernel/sched/idle.c:158 [inline]
       cpuidle_idle_call kernel/sched/idle.c:239 [inline]
       do_idle+0x3e8/0x670 kernel/sched/idle.c:306
       cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403
       start_kernel+0x4bf/0x56e init/main.c:1138
       secondary_startup_64_no_verify+0xc4/0xcb

-> #1 (&port_lock_key){-.-.}-{2:2}:
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5639
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       serial8250_console_write+0x19c/0xf30 drivers/tty/serial/8250/8250_port.c:3351
       console_unlock+0xb00/0xe90 kernel/printk/printk.c:2711
       vprintk_emit+0xba/0x140 kernel/printk/printk.c:2245
       _printk+0xcf/0x118 kernel/printk/printk.c:2266
       register_console+0x72c/0xa20 kernel/printk/printk.c:3064
       univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:679
       console_init+0x52/0x97 kernel/printk/printk.c:3164
       start_kernel+0x32d/0x56e init/main.c:1067
       secondary_startup_64_no_verify+0xc4/0xcb

-> #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+0x1dfb/0x8250 kernel/locking/lockdep.c:3801
       __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5027
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5639
       console_lock_spinning_enable+0x52/0x60 kernel/printk/printk.c:1781
       console_unlock+0x834/0xe90 kernel/printk/printk.c:2708
       vprintk_emit+0xba/0x140 kernel/printk/printk.c:2245
       _printk+0xcf/0x118 kernel/printk/printk.c:2266
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail+0x366/0x4b0 lib/fault-inject.c:146
       should_failslab+0x5/0x20 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+0x94/0x380 mm/slub.c:4420
       kmalloc include/linux/slab.h:586 [inline]
       tty_buffer_alloc drivers/tty/tty_buffer.c:178 [inline]
       __tty_buffer_request_room+0x1f0/0x540 drivers/tty/tty_buffer.c:274
       tty_insert_flip_string_fixed_flag+0x92/0x2c0 drivers/tty/tty_buffer.c:321
       tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
       pty_write+0xe9/0x170 drivers/tty/pty.c:122
       tty_send_xchar+0x25e/0x4d0 drivers/tty/tty_io.c:1168
       tty_ioctl+0xfec/0x1830 drivers/tty/tty_io.c:2787
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

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.4/29521:
 #0: ffff88804056a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffff88804056a130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
 #1: ffff88804056a130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_send_xchar+0x1a4/0x4d0 drivers/tty/tty_io.c:1162
 #2: ffff88804056a2e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: tty_send_xchar+0x1d1/0x4d0 drivers/tty/tty_io.c:1165
 #3: ffff8880736f6158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc5/0x170 drivers/tty/pty.c:120
 #4: ffffffff8c9f94a0 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0xa1/0x140 kernel/printk/printk.c:2244

stack backtrace:
CPU: 1 PID: 29521 Comm: syz-executor.4 Not tainted 5.17.0-rc5-syzkaller-00006-g917bbdb107f8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 check_noncircular+0x2f9/0x3b0 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+0x1dfb/0x8250 kernel/locking/lockdep.c:3801
 __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5027
 lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5639
 console_lock_spinning_enable+0x52/0x60 kernel/printk/printk.c:1781
 console_unlock+0x834/0xe90 kernel/printk/printk.c:2708
 vprintk_emit+0xba/0x140 kernel/printk/printk.c:2245
 _printk+0xcf/0x118 kernel/printk/printk.c:2266
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail+0x366/0x4b0 lib/fault-inject.c:146
 should_failslab+0x5/0x20 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+0x94/0x380 mm/slub.c:4420
 kmalloc include/linux/slab.h:586 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:178 [inline]
 __tty_buffer_request_room+0x1f0/0x540 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x92/0x2c0 drivers/tty/tty_buffer.c:321
 tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
 pty_write+0xe9/0x170 drivers/tty/pty.c:122
 tty_send_xchar+0x25e/0x4d0 drivers/tty/tty_io.c:1168
 tty_ioctl+0xfec/0x1830 drivers/tty/tty_io.c:2787
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f55f3247059
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55f1b9b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f55f335a030 RCX: 00007f55f3247059
RDX: 0000000000000003 RSI: 000000000000540a RDI: 0000000000000003
RBP: 00007f55f1b9b1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffde49e97f R14: 00007f55f1b9b300 R15: 0000000000022000
 </TASK>
CPU: 1 PID: 29521 Comm: syz-executor.4 Not tainted 5.17.0-rc5-syzkaller-00006-g917bbdb107f8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail+0x384/0x4b0 lib/fault-inject.c:146
 should_failslab+0x5/0x20 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+0x94/0x380 mm/slub.c:4420
 kmalloc include/linux/slab.h:586 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:178 [inline]
 __tty_buffer_request_room+0x1f0/0x540 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x92/0x2c0 drivers/tty/tty_buffer.c:321
 tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
 pty_write+0xe9/0x170 drivers/tty/pty.c:122
 tty_send_xchar+0x25e/0x4d0 drivers/tty/tty_io.c:1168
 tty_ioctl+0xfec/0x1830 drivers/tty/tty_io.c:2787
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f55f3247059
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55f1b9b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f55f335a030 RCX: 00007f55f3247059
RDX: 0000000000000003 RSI: 000000000000540a RDI: 0000000000000003
RBP: 00007f55f1b9b1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffde49e97f R14: 00007f55f1b9b300 R15: 0000000000022000
 </TASK>