FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
5.18.0-rc6-syzkaller-00009-gfeb9c5e19e91 #0 Not tainted
------------------------------------------------------
syz-executor.4/6453 is trying to acquire lock:
ffffffff8cb0f4a0 (console_owner){....}-{0:0}, at: console_trylock_spinning+0x1e2/0x450 kernel/printk/printk.c:1878

but task is already holding lock:
ffff88802cb6e958 (&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+0x1a7/0x400 kernel/locking/lockdep.c:5641
       __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 drivers/tty/tty_port.c:306 [inline]
       tty_port_default_wakeup+0x21/0x100 drivers/tty/tty_port.c:48
       serial8250_tx_chars+0x60e/0x810 drivers/tty/serial/8250/8250_port.c:1866
       serial8250_handle_irq+0x32f/0x410 drivers/tty/serial/8250/8250_port.c:1953
       serial8250_default_handle_irq+0xaf/0x190 drivers/tty/serial/8250/8250_port.c:1970
       serial8250_interrupt+0xa3/0x1e0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x200/0x620 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:817
       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+0x9f/0xc0 arch/x86/kernel/irq.c:240
       asm_common_interrupt+0x1e/0x40
       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:110 [inline]
       acpi_idle_do_entry drivers/acpi/processor_idle.c:551 [inline]
       acpi_idle_enter+0x42d/0x790 drivers/acpi/processor_idle.c:686
       cpuidle_enter_state+0x517/0xed0 drivers/cpuidle/cpuidle.c:237
       cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351
       call_cpuidle kernel/sched/idle.c:155 [inline]
       cpuidle_idle_call kernel/sched/idle.c:236 [inline]
       do_idle+0x3d2/0x640 kernel/sched/idle.c:303
       cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
       rest_init+0x24f/0x270 init/main.c:726
       start_kernel+0x0/0x56e init/main.c:882
       start_kernel+0x4bf/0x56e init/main.c:1140
       secondary_startup_64_no_verify+0xc4/0xcb

-> #1 (&port_lock_key){-...}-{2:2}:
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641
       __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/0xf60 drivers/tty/serial/8250/8250_port.c:3358
       console_unlock+0xa98/0x1150 kernel/printk/printk.c:2774
       vprintk_emit+0xd1/0x1e0 kernel/printk/printk.c:2272
       _printk+0xcf/0x10f kernel/printk/printk.c:2293
       register_console+0x6e2/0x9c0 kernel/printk/printk.c:3131
       univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:679
       console_init+0x5d/0xa8 kernel/printk/printk.c:3231
       start_kernel+0x328/0x56e init/main.c:1068
       secondary_startup_64_no_verify+0xc4/0xcb

-> #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+0x185c/0x65c0 kernel/locking/lockdep.c:3803
       __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5029
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641
       console_trylock_spinning+0x202/0x450 kernel/printk/printk.c:1895
       vprintk_emit+0xb8/0x1e0 kernel/printk/printk.c:2271
       _printk+0xcf/0x10f kernel/printk/printk.c:2293
       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: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+0x8b/0x370 mm/slub.c:4410
       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+0x91/0x2c0 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
       process_output_block drivers/tty/n_tty.c:581 [inline]
       n_tty_write+0xe4f/0x13b0 drivers/tty/n_tty.c:2248
       do_tty_write drivers/tty/tty_io.c:1024 [inline]
       file_tty_write+0x5a5/0x960 drivers/tty/tty_io.c:1095
       call_write_iter include/linux/fs.h:2050 [inline]
       new_sync_write fs/read_write.c:504 [inline]
       vfs_write+0xa22/0xd40 fs/read_write.c:591
       ksys_write+0x19b/0x2c0 fs/read_write.c:644
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x2b/0x70 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.4/6453:
 #0: ffff88802015b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffff88802015b130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
 #1: ffff88802015b130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:973 [inline]
 #1: ffff88802015b130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write+0x26e/0x960 drivers/tty/tty_io.c:1095
 #2: ffff88802015b2e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_write+0x244/0x13b0 drivers/tty/n_tty.c:2231
 #3: ffffc9000b5d1378 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:536 [inline]
 #3: ffffc9000b5d1378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x707/0x13b0 drivers/tty/n_tty.c:2248
 #4: ffff88802cb6e958 (&port->lock){-...}-{2:2}, at: pty_write+0xc5/0x170 drivers/tty/pty.c:120

stack backtrace:
CPU: 1 PID: 6453 Comm: syz-executor.4 Not tainted 5.18.0-rc6-syzkaller-00009-gfeb9c5e19e91 #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+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f7/0x3b0 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+0x185c/0x65c0 kernel/locking/lockdep.c:3803
 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5029
 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641
 console_trylock_spinning+0x202/0x450 kernel/printk/printk.c:1895
 vprintk_emit+0xb8/0x1e0 kernel/printk/printk.c:2271
 _printk+0xcf/0x10f kernel/printk/printk.c:2293
 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: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+0x8b/0x370 mm/slub.c:4410
 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+0x91/0x2c0 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
 process_output_block drivers/tty/n_tty.c:581 [inline]
 n_tty_write+0xe4f/0x13b0 drivers/tty/n_tty.c:2248
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write+0x5a5/0x960 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0xa22/0xd40 fs/read_write.c:591
 ksys_write+0x19b/0x2c0 fs/read_write.c:644
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f998f2890e9
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:00007f998e1fe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f998f39bf60 RCX: 00007f998f2890e9
RDX: 00000000fffffedf RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f998e1fe1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffa844bb1f R14: 00007f998e1fe300 R15: 0000000000022000
 </TASK>
CPU: 1 PID: 6453 Comm: syz-executor.4 Not tainted 5.18.0-rc6-syzkaller-00009-gfeb9c5e19e91 #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+0x1e3/0x2cb 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: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+0x8b/0x370 mm/slub.c:4410
 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+0x91/0x2c0 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
 process_output_block drivers/tty/n_tty.c:581 [inline]
 n_tty_write+0xe4f/0x13b0 drivers/tty/n_tty.c:2248
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write+0x5a5/0x960 drivers/tty/tty_io.c:1095
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0xa22/0xd40 fs/read_write.c:591
 ksys_write+0x19b/0x2c0 fs/read_write.c:644
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f998f2890e9
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:00007f998e1fe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f998f39bf60 RCX: 00007f998f2890e9
RDX: 00000000fffffedf RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f998e1fe1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffa844bb1f R14: 00007f998e1fe300 R15: 0000000000022000
 </TASK>