syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Not tainted
-----------------------------------------------------
syz.8.13038/20792 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff888037baa468 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
ffff888037baa468 (&tty->flow.lock){....}-{3:3}, at: stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765

and this task is already holding:
ffffffff8e7709f8 (kbd_event_lock){..-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffffffff8e7709f8 (kbd_event_lock){..-.}-{3:3}, at: kbd_event+0xd2/0x3f70 drivers/tty/vt/keyboard.c:1528
which would create a new lock dependency:
 (kbd_event_lock){..-.}-{3:3} -> (&tty->flow.lock){....}-{3:3}

but this new dependency connects a SOFTIRQ-irq-safe lock:
 (kbd_event_lock){..-.}-{3:3}

... which became SOFTIRQ-irq-safe at:
  lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
  __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
  _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
  spin_lock include/linux/spinlock.h:351 [inline]
  kbd_event+0xd2/0x3f70 drivers/tty/vt/keyboard.c:1528
  input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541
  input_pass_values+0x288/0x890 drivers/input/input.c:128
  input_event_dispose+0x3e5/0x6b0 drivers/input/input.c:353
  input_event+0x89/0xe0 drivers/input/input.c:396
  hidinput_hid_event+0x145e/0x1dd0 drivers/hid/hid-input.c:1731
  hid_process_event+0x4be/0x620 drivers/hid/hid-core.c:1565
  hid_process_report drivers/hid/hid-core.c:1713 [inline]
  hid_report_raw_event+0xe91/0x16d0 drivers/hid/hid-core.c:2074
  __hid_input_report drivers/hid/hid-core.c:2144 [inline]
  hid_input_report+0x43e/0x520 drivers/hid/hid-core.c:2166
  hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
  __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661
  dummy_timer+0x85f/0x44c0 drivers/usb/gadget/udc/dummy_hcd.c:1995
  __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
  __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
  hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858
  handle_softirqs+0x27d/0x850 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
  netconsole_netdev_event+0x4/0x780 drivers/net/netconsole.c:1435
  notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
  call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
  call_netdevice_notifiers net/core/dev.c:2281 [inline]
  __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
  netif_change_flags+0xe8/0x1a0 net/core/dev.c:9705
  do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3151
  rtnl_changelink net/core/rtnetlink.c:3769 [inline]
  __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
  rtnl_newlink+0x1619/0x1c80 net/core/rtnetlink.c:4065
  rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951
  netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
  netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
  sock_sendmsg_nosec net/socket.c:718 [inline]
  __sock_sendmsg+0x21c/0x270 net/socket.c:733
  __sys_sendto+0x3bd/0x520 net/socket.c:2222
  __do_sys_sendto net/socket.c:2229 [inline]
  __se_sys_sendto net/socket.c:2225 [inline]
  __x64_sys_sendto+0xde/0x100 net/socket.c:2225
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

to a SOFTIRQ-irq-unsafe lock:
 (tasklist_lock){.+.+}-{3:3}

... which became SOFTIRQ-irq-unsafe at:
...
  lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
  __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
  _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
  __do_wait+0xde/0x740 kernel/exit.c:1674
  do_wait+0x1e8/0x4f0 kernel/exit.c:1718
  kernel_wait+0xab/0x170 kernel/exit.c:1894
  call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
  call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
  process_one_work kernel/workqueue.c:3263 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

other info that might help us debug this:

Chain exists of:
  kbd_event_lock --> &tty->flow.lock --> tasklist_lock

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(tasklist_lock);
                               local_irq_disable();
                               lock(kbd_event_lock);
                               lock(&tty->flow.lock);
  <Interrupt>
    lock(kbd_event_lock);

 *** DEADLOCK ***

5 locks held by syz.8.13038/20792:
 #0: ffff8880291ce118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_write+0x1a1/0x480 drivers/input/evdev.c:511
 #1: ffff8880291ca230 (&dev->event_lock#2){..-.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
 #1: ffff8880291ca230 (&dev->event_lock#2){..-.}-{3:3}, at: input_inject_event+0xa5/0x340 drivers/input/input.c:419
 #2: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #2: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 #2: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: input_inject_event+0xb6/0x340 drivers/input/input.c:420
 #3: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #3: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #3: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 #3: ffffffff8df41d40 (rcu_read_lock){....}-{1:3}, at: input_pass_values+0x8d/0x890 drivers/input/input.c:119
 #4: ffffffff8e7709f8 (kbd_event_lock){..-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #4: ffffffff8e7709f8 (kbd_event_lock){..-.}-{3:3}, at: kbd_event+0xd2/0x3f70 drivers/tty/vt/keyboard.c:1528

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (kbd_event_lock){..-.}-{3:3} {
   IN-SOFTIRQ-W at:
                    lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                    __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
                    _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
                    spin_lock include/linux/spinlock.h:351 [inline]
                    kbd_event+0xd2/0x3f70 drivers/tty/vt/keyboard.c:1528
                    input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541
                    input_pass_values+0x288/0x890 drivers/input/input.c:128
                    input_event_dispose+0x3e5/0x6b0 drivers/input/input.c:353
                    input_event+0x89/0xe0 drivers/input/input.c:396
                    hidinput_hid_event+0x145e/0x1dd0 drivers/hid/hid-input.c:1731
                    hid_process_event+0x4be/0x620 drivers/hid/hid-core.c:1565
                    hid_process_report drivers/hid/hid-core.c:1713 [inline]
                    hid_report_raw_event+0xe91/0x16d0 drivers/hid/hid-core.c:2074
                    __hid_input_report drivers/hid/hid-core.c:2144 [inline]
                    hid_input_report+0x43e/0x520 drivers/hid/hid-core.c:2166
                    hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
                    __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661
                    dummy_timer+0x85f/0x44c0 drivers/usb/gadget/udc/dummy_hcd.c:1995
                    __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
                    __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
                    hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858
                    handle_softirqs+0x27d/0x850 kernel/softirq.c:622
                    __do_softirq kernel/softirq.c:656 [inline]
                    invoke_softirq kernel/softirq.c:496 [inline]
                    __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
                    irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
                    instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
                    sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
                    asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
                    netconsole_netdev_event+0x4/0x780 drivers/net/netconsole.c:1435
                    notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
                    call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
                    call_netdevice_notifiers net/core/dev.c:2281 [inline]
                    __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
                    netif_change_flags+0xe8/0x1a0 net/core/dev.c:9705
                    do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3151
                    rtnl_changelink net/core/rtnetlink.c:3769 [inline]
                    __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
                    rtnl_newlink+0x1619/0x1c80 net/core/rtnetlink.c:4065
                    rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951
                    netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
                    netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
                    netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
                    netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
                    sock_sendmsg_nosec net/socket.c:718 [inline]
                    __sock_sendmsg+0x21c/0x270 net/socket.c:733
                    __sys_sendto+0x3bd/0x520 net/socket.c:2222
                    __do_sys_sendto net/socket.c:2229 [inline]
                    __se_sys_sendto net/socket.c:2225 [inline]
                    __x64_sys_sendto+0xde/0x100 net/socket.c:2225
                    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                    do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
                    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL USE at:
                   lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                   _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
                   vt_reset_unicode+0x2b/0x160 drivers/tty/vt/keyboard.c:2187
                   reset_vc+0x68/0x1b0 drivers/tty/vt/vt_ioctl.c:966
                   vc_init+0x70/0x4a0 drivers/tty/vt/vt.c:3728
                   con_init+0x385/0x9c0 drivers/tty/vt/vt.c:3793
                   console_init+0xfc/0x3f0 kernel/printk/printk.c:4298
                   start_kernel+0x254/0x410 init/main.c:1048
                   x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
                   x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
                   common_startup_64+0x13e/0x147
 }
 ... key      at: [<ffffffff8e7709f8>] kbd_event_lock+0x18/0xa0 keyboard.c:-1

the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
   -> (tasklist_lock){.+.+}-{3:3} {
      HARDIRQ-ON-R at:
                          lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                          __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                          _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                          __do_wait+0xde/0x740 kernel/exit.c:1674
                          do_wait+0x1e8/0x4f0 kernel/exit.c:1718
                          kernel_wait+0xab/0x170 kernel/exit.c:1894
                          call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                          call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                          process_one_work kernel/workqueue.c:3263 [inline]
                          process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346
                          worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
                          kthread+0x711/0x8a0 kernel/kthread.c:463
                          ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
                          ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
      SOFTIRQ-ON-R at:
                          lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                          __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                          _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                          __do_wait+0xde/0x740 kernel/exit.c:1674
                          do_wait+0x1e8/0x4f0 kernel/exit.c:1718
                          kernel_wait+0xab/0x170 kernel/exit.c:1894
                          call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                          call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                          process_one_work kernel/workqueue.c:3263 [inline]
                          process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346
                          worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
                          kthread+0x711/0x8a0 kernel/kthread.c:463
                          ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
                          ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
      INITIAL USE at:
                         lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                         __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
                         _raw_write_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:326
                         copy_process+0x2185/0x3950 kernel/fork.c:2325
                         kernel_clone+0x21e/0x820 kernel/fork.c:2609
                         user_mode_thread+0xdd/0x140 kernel/fork.c:2685
                         rest_init+0x23/0x300 init/main.c:722
                         start_kernel+0x3ae/0x410 init/main.c:1111
                         x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
                         x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
                         common_startup_64+0x13e/0x147
      INITIAL READ USE at:
                              lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                              __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                              _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                              __do_wait+0xde/0x740 kernel/exit.c:1674
                              do_wait+0x1e8/0x4f0 kernel/exit.c:1718
                              kernel_wait+0xab/0x170 kernel/exit.c:1894
                              call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                              call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                              process_one_work kernel/workqueue.c:3263 [inline]
                              process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346
                              worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
                              kthread+0x711/0x8a0 kernel/kthread.c:463
                              ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
                              ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
    }
    ... key      at: [<ffffffff8dc0c058>] tasklist_lock+0x18/0x40
    ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
   _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
   send_sigio+0x101/0x370 fs/fcntl.c:932
   dnotify_handle_event+0x169/0x440 fs/notify/dnotify/dnotify.c:113
   fsnotify_handle_event fs/notify/fsnotify.c:376 [inline]
   send_to_group fs/notify/fsnotify.c:424 [inline]
   fsnotify+0x1814/0x1a80 fs/notify/fsnotify.c:641
   fsnotify_name include/linux/fsnotify.h:55 [inline]
   fsnotify_dirent include/linux/fsnotify.h:61 [inline]
   fsnotify_create include/linux/fsnotify.h:323 [inline]
   open_last_lookups fs/namei.c:4543 [inline]
   path_openat+0x1aa1/0x3dd0 fs/namei.c:4784
   do_filp_open+0x1fa/0x410 fs/namei.c:4814
   do_sys_openat2+0x121/0x200 fs/open.c:1430
   do_sys_open fs/open.c:1436 [inline]
   __do_sys_openat fs/open.c:1452 [inline]
   __se_sys_openat fs/open.c:1447 [inline]
   __x64_sys_openat+0x138/0x170 fs/open.c:1447
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  -> (&f_owner->lock){....}-{3:3} {
     INITIAL USE at:
                       lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                       __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
                       _raw_write_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:326
                       __f_setown+0x67/0x370 fs/fcntl.c:136
                       generic_add_lease fs/locks.c:1895 [inline]
                       generic_setlease+0xe1e/0x1280 fs/locks.c:1971
                       do_fcntl_add_lease+0x34d/0x460 fs/locks.c:2074
                       fcntl_setlease+0x123/0x180 fs/locks.c:2099
                       do_fcntl+0x867/0x1a50 fs/fcntl.c:535
                       __do_sys_fcntl fs/fcntl.c:602 [inline]
                       __se_sys_fcntl+0xc8/0x150 fs/fcntl.c:587
                       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                       do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
                       entry_SYSCALL_64_after_hwframe+0x77/0x7f
     INITIAL READ USE at:
                            lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                            __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline]
                            _raw_read_lock_irqsave+0xaf/0x100 kernel/locking/spinlock.c:236
                            send_sigio+0x38/0x370 fs/fcntl.c:918
                            kill_fasync_rcu fs/fcntl.c:1144 [inline]
                            kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159
                            sock_wake_async+0x137/0x160 net/socket.c:-1
                            sk_wake_async+0x184/0x280 include/net/sock.h:2539
                            unix_release_sock+0x65e/0xc10 net/unix/af_unix.c:712
                            unix_release+0x92/0xd0 net/unix/af_unix.c:1196
                            __sock_release net/socket.c:653 [inline]
                            sock_close+0xc3/0x240 net/socket.c:1446
                            __fput+0x44c/0xa70 fs/file_table.c:468
                            task_work_run+0x1d4/0x260 kernel/task_work.c:233
                            get_signal+0x11ec/0x1340 kernel/signal.c:2807
                            arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
                            __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
                            exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
                            __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
                            syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
                            syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
                            syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
                            do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
                            entry_SYSCALL_64_after_hwframe+0x77/0x7f
   }
   ... key      at: [<ffffffff99887a60>] file_f_owner_allocate.__key+0x0/0x20
   ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline]
   _raw_read_lock_irqsave+0xaf/0x100 kernel/locking/spinlock.c:236
   send_sigio+0x38/0x370 fs/fcntl.c:918
   kill_fasync_rcu fs/fcntl.c:1144 [inline]
   kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159
   sock_wake_async+0x137/0x160 net/socket.c:-1
   sk_wake_async+0x184/0x280 include/net/sock.h:2539
   unix_release_sock+0x65e/0xc10 net/unix/af_unix.c:712
   unix_release+0x92/0xd0 net/unix/af_unix.c:1196
   __sock_release net/socket.c:653 [inline]
   sock_close+0xc3/0x240 net/socket.c:1446
   __fput+0x44c/0xa70 fs/file_table.c:468
   task_work_run+0x1d4/0x260 kernel/task_work.c:233
   get_signal+0x11ec/0x1340 kernel/signal.c:2807
   arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
   __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
   exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
   __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
   syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
   syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
   syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
   do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

 -> (&new->fa_lock){....}-{3:3} {
    INITIAL USE at:
                     lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
                     _raw_write_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:326
                     fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012
                     pipe_fasync+0xa9/0x1e0 fs/pipe.c:756
                     __fput+0x8a2/0xa70 fs/file_table.c:465
                     task_work_run+0x1d4/0x260 kernel/task_work.c:233
                     resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
                     __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
                     exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
                     __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
                     syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
                     syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
                     syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
                     do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
                     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL READ USE at:
                          lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                          __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline]
                          _raw_read_lock_irqsave+0xaf/0x100 kernel/locking/spinlock.c:236
                          kill_fasync_rcu fs/fcntl.c:1135 [inline]
                          kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                          wakeup_pipe_readers fs/splice.c:183 [inline]
                          splice_file_to_pipe+0x344/0x440 fs/splice.c:1295
                          do_splice+0xdc0/0x1660 fs/splice.c:1376
                          __do_splice fs/splice.c:1433 [inline]
                          __do_sys_splice fs/splice.c:1636 [inline]
                          __se_sys_splice+0x2e1/0x460 fs/splice.c:1618
                          do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                          do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
                          entry_SYSCALL_64_after_hwframe+0x77/0x7f
  }
  ... key      at: [<ffffffff99887a80>] fasync_insert_entry.__key+0x0/0x20
  ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline]
   _raw_read_lock_irqsave+0xaf/0x100 kernel/locking/spinlock.c:236
   kill_fasync_rcu fs/fcntl.c:1135 [inline]
   kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
   tty_wakeup drivers/tty/tty_io.c:515 [inline]
   __start_tty+0x18c/0x220 drivers/tty/tty_io.c:777
   start_tty+0x2b/0x70 drivers/tty/tty_io.c:794
   n_tty_set_termios+0xa7c/0x1090 drivers/tty/n_tty.c:1858
   tty_set_termios+0xda4/0x17e0 drivers/tty/tty_ioctl.c:348
   set_termios+0x516/0x6c0 drivers/tty/tty_ioctl.c:516
   tty_mode_ioctl+0x47e/0x740 drivers/tty/tty_ioctl.c:-1
   tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:597 [inline]
   __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> (&tty->flow.lock){....}-{3:3} {
   INITIAL USE at:
                   lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                   _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
                   class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
                   start_tty+0x20/0x70 drivers/tty/tty_io.c:793
                   n_tty_set_termios+0xa7c/0x1090 drivers/tty/n_tty.c:1858
                   tty_set_termios+0xda4/0x17e0 drivers/tty/tty_ioctl.c:348
                   set_termios+0x516/0x6c0 drivers/tty/tty_ioctl.c:516
                   tty_mode_ioctl+0x47e/0x740 drivers/tty/tty_ioctl.c:-1
                   tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
                   vfs_ioctl fs/ioctl.c:51 [inline]
                   __do_sys_ioctl fs/ioctl.c:597 [inline]
                   __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
                   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                   do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff99b64e00>] alloc_tty_struct.__key.35+0x0/0x20
 ... acquired at:
   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
   _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
   class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
   stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765
   kbd_keycode drivers/tty/vt/keyboard.c:1515 [inline]
   kbd_event+0x2b72/0x3f70 drivers/tty/vt/keyboard.c:1534
   input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541
   input_pass_values+0x288/0x890 drivers/input/input.c:128
   input_event_dispose+0x330/0x6b0 drivers/input/input.c:342
   input_inject_event+0x1dd/0x340 drivers/input/input.c:424
   evdev_write+0x2fc/0x480 drivers/input/evdev.c:528
   vfs_write+0x27e/0xb30 fs/read_write.c:684
   ksys_write+0x145/0x250 fs/read_write.c:738
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


stack backtrace:
CPU: 1 UID: 0 PID: 20792 Comm: syz.8.13038 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_bad_irq_dependency kernel/locking/lockdep.c:2616 [inline]
 check_irq_usage kernel/locking/lockdep.c:2857 [inline]
 check_prev_add kernel/locking/lockdep.c:3169 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x2a95/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
 stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765
 kbd_keycode drivers/tty/vt/keyboard.c:1515 [inline]
 kbd_event+0x2b72/0x3f70 drivers/tty/vt/keyboard.c:1534
 input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541
 input_pass_values+0x288/0x890 drivers/input/input.c:128
 input_event_dispose+0x330/0x6b0 drivers/input/input.c:342
 input_inject_event+0x1dd/0x340 drivers/input/input.c:424
 evdev_write+0x2fc/0x480 drivers/input/evdev.c:528
 vfs_write+0x27e/0xb30 fs/read_write.c:684
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f71ad78f749
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f71ae5ea038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f71ad9e6090 RCX: 00007f71ad78f749
RDX: 0000000000002250 RSI: 0000200000000040 RDI: 0000000000000009
RBP: 00007f71ad813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f71ad9e6128 R14: 00007f71ad9e6090 R15: 00007f71adb0fa28
 </TASK>