syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.7.12181/9658 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff8880837000c0 (&new->fa_lock){...-}-{3:3}, at: kill_fasync_rcu fs/fcntl.c:1135 [inline]
ffff8880837000c0 (&new->fa_lock){...-}-{3:3}, at: kill_fasync+0x199/0x4d0 fs/fcntl.c:1159

and this task is already holding:
ffff88802ae82440 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
ffff88802ae82440 (&tty->flow.lock){....}-{3:3}, at: start_tty+0x1b/0x50 drivers/tty/tty_io.c:793
which would create a new lock dependency:
 (&tty->flow.lock){....}-{3:3} -> (&new->fa_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+0x106/0x350 kernel/locking/lockdep.c:5868
  __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
  _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
  spin_lock include/linux/spinlock.h:342 [inline]
  class_spinlock_constructor include/linux/spinlock.h:587 [inline]
  kbd_event+0xd7/0x42f0 drivers/tty/vt/keyboard.c:1578
  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_event+0x84/0xc0 drivers/input/input.c:396
  input_sync include/linux/input.h:464 [inline]
  imon_incoming_packet+0x1ccf/0x31c0 drivers/media/rc/imon.c:1707
  usb_rx_callback_intf0+0xba/0x210 drivers/media/rc/imon.c:1769
  __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1657
  dummy_timer+0xbc0/0x4650 drivers/usb/gadget/udc/dummy_hcd.c:2005
  __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
  __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
  hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2011
  handle_softirqs+0x22a/0x840 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
  lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
  rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
  rcu_read_lock include/linux/rcupdate.h:838 [inline]
  mntput_no_expire+0x38/0x1c0 fs/namespace.c:1391
  __simple_recursive_removal+0x215/0x520 fs/libfs.c:624
  debugfs_remove+0x5b/0x70 fs/debugfs/inode.c:781
  kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:988 [inline]
  kvm_destroy_vm virt/kvm/kvm_main.c:1261 [inline]
  kvm_put_kvm+0x13e/0xa50 virt/kvm/kvm_main.c:1331
  kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1354
  __fput+0x44f/0xa60 fs/file_table.c:510
  task_work_run+0x1d9/0x270 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:67 [inline]
  exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
  __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
  syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
  syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
  do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
  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+0x106/0x350 kernel/locking/lockdep.c:5868
  __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
  _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
  __do_wait+0xde/0x740 kernel/exit.c:1677
  do_wait+0x1e7/0x510 kernel/exit.c:1721
  kernel_wait+0xd6/0x1c0 kernel/exit.c:1897
  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:3302 [inline]
  process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
  kthread+0x388/0x470 kernel/kthread.c:436
  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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 ***

6 locks held by syz.7.12181/9658:
 #0: ffff88802ae820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffff88802ae822c8 (&tty->termios_rwsem/1){++++}-{4:4}, at: tty_set_termios+0x147/0x1800 drivers/tty/tty_ioctl.c:333
 #2: ffff88802ae820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #3: ffff88802ae82440 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
 #3: ffff88802ae82440 (&tty->flow.lock){....}-{3:3}, at: start_tty+0x1b/0x50 drivers/tty/tty_io.c:793
 #4: ffff88802ae820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #5: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #5: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #5: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: kill_fasync+0x53/0x4d0 fs/fcntl.c:1158

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
 -> (kbd_event_lock){..-.}-{3:3} {
    IN-SOFTIRQ-W at:
                      lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                      __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
                      _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
                      spin_lock include/linux/spinlock.h:342 [inline]
                      class_spinlock_constructor include/linux/spinlock.h:587 [inline]
                      kbd_event+0xd7/0x42f0 drivers/tty/vt/keyboard.c:1578
                      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_event+0x84/0xc0 drivers/input/input.c:396
                      input_sync include/linux/input.h:464 [inline]
                      imon_incoming_packet+0x1ccf/0x31c0 drivers/media/rc/imon.c:1707
                      usb_rx_callback_intf0+0xba/0x210 drivers/media/rc/imon.c:1769
                      __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1657
                      dummy_timer+0xbc0/0x4650 drivers/usb/gadget/udc/dummy_hcd.c:2005
                      __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
                      __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
                      hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2011
                      handle_softirqs+0x22a/0x840 kernel/softirq.c:622
                      __do_softirq kernel/softirq.c:656 [inline]
                      invoke_softirq kernel/softirq.c:496 [inline]
                      __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
                      irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
                      instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
                      sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
                      asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
                      lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
                      rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
                      rcu_read_lock include/linux/rcupdate.h:838 [inline]
                      mntput_no_expire+0x38/0x1c0 fs/namespace.c:1391
                      __simple_recursive_removal+0x215/0x520 fs/libfs.c:624
                      debugfs_remove+0x5b/0x70 fs/debugfs/inode.c:781
                      kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:988 [inline]
                      kvm_destroy_vm virt/kvm/kvm_main.c:1261 [inline]
                      kvm_put_kvm+0x13e/0xa50 virt/kvm/kvm_main.c:1331
                      kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1354
                      __fput+0x44f/0xa60 fs/file_table.c:510
                      task_work_run+0x1d9/0x270 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:67 [inline]
                      exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
                      __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
                      syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
                      syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
                      do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
                      entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL USE at:
                     lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                     __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
                     _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
                     class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
                     vt_reset_unicode+0x2b/0x160 drivers/tty/vt/keyboard.c:2194
                     reset_vc+0x68/0x1b0 drivers/tty/vt/vt_ioctl.c:966
                     vc_init+0x70/0x4a0 drivers/tty/vt/vt.c:3823
                     con_init+0x377/0x6a0 drivers/tty/vt/vt.c:3889
                     console_init+0x10b/0x4a0 kernel/printk/printk.c:4407
                     start_kernel+0x230/0x3e0 init/main.c:1157
                     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: [<ffffffff8f209e98>] kbd_event_lock+0x18/0xa0 keyboard.c:-1
-> (&tty->flow.lock){....}-{3:3} {
   INITIAL USE at:
                   lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
                   _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
                   class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
                   start_tty+0x1b/0x50 drivers/tty/tty_io.c:793
                   n_tty_set_termios+0xa7c/0x10a0 drivers/tty/n_tty.c:1848
                   tty_set_termios+0xdb3/0x1800 drivers/tty/tty_ioctl.c:348
                   set_termios+0x566/0x710 drivers/tty/tty_ioctl.c:516
                   tty_mode_ioctl+0x4a6/0x7d0 drivers/tty/tty_ioctl.c:-1
                   tty_ioctl+0x9c5/0xde0 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff9a8184a0>] alloc_tty_struct.__key.35+0x0/0x20
 ... acquired at:
   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
   _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
   class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
   stop_tty+0x2f/0x140 drivers/tty/tty_io.c:765
   kbd_keycode drivers/tty/vt/keyboard.c:1565 [inline]
   kbd_event+0x2f91/0x42f0 drivers/tty/vt/keyboard.c:1583
   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+0x1dc/0x330 drivers/input/input.c:424
   evdev_write+0x325/0x4c0 drivers/input/evdev.c:528
   vfs_write+0x29a/0xb90 fs/read_write.c:686
   ksys_write+0x150/0x270 fs/read_write.c:740
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
  -> (tasklist_lock){.+.+}-{3:3} {
     HARDIRQ-ON-R at:
                        lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                        __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
                        _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
                        __do_wait+0xde/0x740 kernel/exit.c:1677
                        do_wait+0x1e7/0x510 kernel/exit.c:1721
                        kernel_wait+0xd6/0x1c0 kernel/exit.c:1897
                        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:3302 [inline]
                        process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
     SOFTIRQ-ON-R at:
                        lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                        __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
                        _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
                        __do_wait+0xde/0x740 kernel/exit.c:1677
                        do_wait+0x1e7/0x510 kernel/exit.c:1721
                        kernel_wait+0xd6/0x1c0 kernel/exit.c:1897
                        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:3302 [inline]
                        process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
     INITIAL USE at:
                       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                       __raw_write_lock_irq include/linux/rwlock_api_smp.h:213 [inline]
                       _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:330
                       copy_process+0x2b5e/0x4450 kernel/fork.c:2413
                       kernel_clone+0x284/0x8f0 kernel/fork.c:2723
                       user_mode_thread+0x110/0x180 kernel/fork.c:2799
                       rest_init+0x23/0x300 init/main.c:727
                       start_kernel+0x38a/0x3e0 init/main.c:1220
                       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+0x106/0x350 kernel/locking/lockdep.c:5868
                            __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
                            _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
                            __do_wait+0xde/0x740 kernel/exit.c:1677
                            do_wait+0x1e7/0x510 kernel/exit.c:1721
                            kernel_wait+0xd6/0x1c0 kernel/exit.c:1897
                            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:3302 [inline]
                            process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                            worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                            kthread+0x388/0x470 kernel/kthread.c:436
                            ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                            ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   }
   ... key      at: [<ffffffff8e60a058>] tasklist_lock+0x18/0x40
   ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
   _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
   send_sigurg+0x12b/0x420 fs/fcntl.c:978
   sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3672
   queue_oob+0x42c/0x4f0 net/unix/af_unix.c:2358
   unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2492
   sock_sendmsg_nosec net/socket.c:787 [inline]
   __sock_sendmsg net/socket.c:802 [inline]
   ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698
   ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
   __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841
   __do_sys_sendmmsg net/socket.c:2868 [inline]
   __se_sys_sendmmsg net/socket.c:2865 [inline]
   __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

 -> (&f_owner->lock){...-}-{3:3} {
    IN-SOFTIRQ-R at:
                      lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                      __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
                      _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
                      send_sigurg+0x55/0x420 fs/fcntl.c:962
                      sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3672
                      tcp_check_urg+0x200/0x760 net/ipv4/tcp_input.c:6203
                      tcp_urg+0x15d/0x410 net/ipv4/tcp_input.c:6244
                      tcp_rcv_established+0xf7b/0x2800 net/ipv4/tcp_input.c:6647
                      tcp_v4_do_rcv+0x964/0x13c0 net/ipv4/tcp_ipv4.c:1852
                      tcp_v4_rcv+0x2681/0x2ff0 net/ipv4/tcp_ipv4.c:2246
                      ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:207
                      ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
                      NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
                      NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
                      __netif_receive_skb_one_core net/core/dev.c:6209 [inline]
                      __netif_receive_skb net/core/dev.c:6322 [inline]
                      process_backlog+0xaa3/0x1950 net/core/dev.c:6673
                      __napi_poll+0xae/0x340 net/core/dev.c:7737
                      napi_poll net/core/dev.c:7800 [inline]
                      net_rx_action+0x627/0xf70 net/core/dev.c:7957
                      handle_softirqs+0x22a/0x840 kernel/softirq.c:622
                      run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
                      smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
                      kthread+0x388/0x470 kernel/kthread.c:436
                      ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                      ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
    INITIAL USE at:
                     lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:213 [inline]
                     _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:330
                     __f_setown+0x67/0x370 fs/fcntl.c:136
                     fcntl_dirnotify+0x3f9/0x6a0 fs/notify/dnotify/dnotify.c:369
                     do_fcntl+0x77e/0x1a20 fs/fcntl.c:538
                     __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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
                     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL READ USE at:
                          lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                          __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
                          _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
                          send_sigio+0x38/0x370 fs/fcntl.c:918
                          dnotify_handle_event+0x169/0x440 fs/notify/dnotify/dnotify.c:113
                          fsnotify_handle_event fs/notify/fsnotify.c:327 [inline]
                          send_to_group fs/notify/fsnotify.c:375 [inline]
                          fsnotify+0x1831/0x1ae0 fs/notify/fsnotify.c:592
                          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:4614 [inline]
                          path_openat+0x15c2/0x3860 fs/namei.c:4855
                          do_file_open+0x23e/0x4a0 fs/namei.c:4887
                          do_sys_openat2+0x113/0x200 fs/open.c:1364
                          do_sys_open fs/open.c:1370 [inline]
                          __do_sys_creat fs/open.c:1448 [inline]
                          __se_sys_creat fs/open.c:1442 [inline]
                          __x64_sys_creat+0x8f/0xc0 fs/open.c:1442
                          do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                          do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
                          entry_SYSCALL_64_after_hwframe+0x77/0x7f
  }
  ... key      at: [<ffffffff9a538840>] file_f_owner_allocate.__key+0x0/0x20
  ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
   _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
   send_sigio+0x38/0x370 fs/fcntl.c:918
   kill_fasync_rcu fs/fcntl.c:1144 [inline]
   kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159
   lease_break_callback+0x26/0x30 fs/locks.c:577
   __break_lease+0x81f/0x1ea0 fs/locks.c:1669
   break_lease include/linux/filelock.h:485 [inline]
   do_dentry_open+0x1010/0x14e0 fs/open.c:938
   vfs_open+0x3b/0x340 fs/open.c:1079
   do_open fs/namei.c:4699 [inline]
   path_openat+0x2e08/0x3860 fs/namei.c:4858
   do_file_open+0x23e/0x4a0 fs/namei.c:4887
   do_sys_openat2+0x113/0x200 fs/open.c:1364
   do_sys_open fs/open.c:1370 [inline]
   __do_sys_openat fs/open.c:1386 [inline]
   __se_sys_openat fs/open.c:1381 [inline]
   __x64_sys_openat+0x138/0x170 fs/open.c:1381
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> (&new->fa_lock){...-}-{3:3} {
   IN-SOFTIRQ-R at:
                    lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                    __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
                    _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
                    kill_fasync_rcu fs/fcntl.c:1135 [inline]
                    kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                    sock_wake_async+0x137/0x160 net/socket.c:-1
                    sk_wake_async_rcu include/net/sock.h:2593 [inline]
                    sock_def_readable+0x3c1/0x550 net/core/sock.c:3616
                    tcp_data_queue+0x1e6f/0x5ea0 net/ipv4/tcp_input.c:5655
                    tcp_rcv_established+0xf86/0x2800 net/ipv4/tcp_input.c:6650
                    tcp_v4_do_rcv+0x964/0x13c0 net/ipv4/tcp_ipv4.c:1852
                    tcp_v4_rcv+0x2681/0x2ff0 net/ipv4/tcp_ipv4.c:2246
                    ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:207
                    ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
                    NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
                    NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
                    __netif_receive_skb_one_core net/core/dev.c:6209 [inline]
                    __netif_receive_skb net/core/dev.c:6322 [inline]
                    process_backlog+0xaa3/0x1950 net/core/dev.c:6673
                    __napi_poll+0xae/0x340 net/core/dev.c:7737
                    napi_poll net/core/dev.c:7800 [inline]
                    net_rx_action+0x627/0xf70 net/core/dev.c:7957
                    handle_softirqs+0x22a/0x840 kernel/softirq.c:622
                    do_softirq+0x76/0xd0 kernel/softirq.c:523
                    __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
                    sk_stream_wait_memory+0x72b/0xf80 net/core/stream.c:149
                    tcp_sendmsg_locked+0x238a/0x5360 net/ipv4/tcp.c:1408
                    tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1455
                    sock_sendmsg_nosec net/socket.c:787 [inline]
                    __sock_sendmsg net/socket.c:802 [inline]
                    __sys_sendto+0x5de/0x710 net/socket.c:2265
                    __do_sys_sendto net/socket.c:2272 [inline]
                    __se_sys_sendto net/socket.c:2268 [inline]
                    __x64_sys_sendto+0xde/0x100 net/socket.c:2268
                    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                    do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
                    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL USE at:
                   lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:213 [inline]
                   _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:330
                   fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012
                   sock_fasync+0x85/0xf0 net/socket.c:1539
                   __fput+0x890/0xa60 fs/file_table.c:507
                   task_work_run+0x1d9/0x270 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:67 [inline]
                   exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
                   __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
                   syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
                   syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
                   do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL READ USE at:
                        lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                        __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
                        _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
                        kill_fasync_rcu fs/fcntl.c:1135 [inline]
                        kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                        sock_wake_async+0x137/0x160 net/socket.c:-1
                        sk_wake_async_rcu include/net/sock.h:2593 [inline]
                        sctp_data_ready+0x3c1/0x550 net/sctp/socket.c:9328
                        sctp_ulpq_tail_event+0x7be/0xb10 net/sctp/ulpqueue.c:254
                        do_ulpq_tail_event+0x136/0x1a0 net/sctp/stream_interleave.c:1295
                        sctp_assoc_ulpevent_type_set net/sctp/socket.c:4281 [inline]
                        sctp_setsockopt_event+0x887/0xd20 net/sctp/socket.c:4321
                        sctp_setsockopt+0xb0d/0x12c0 net/sctp/socket.c:4759
                        do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2381
                        __sys_setsockopt net/socket.c:2406 [inline]
                        __do_sys_setsockopt net/socket.c:2412 [inline]
                        __se_sys_setsockopt net/socket.c:2409 [inline]
                        __x64_sys_setsockopt+0x13d/0x1b0 net/socket.c:2409
                        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                        do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
                        entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff9a538860>] fasync_insert_entry.__key+0x0/0x20
 ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
   _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
   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+0x26/0x50 drivers/tty/tty_io.c:794
   n_tty_set_termios+0xa7c/0x10a0 drivers/tty/n_tty.c:1848
   tty_set_termios+0xdb3/0x1800 drivers/tty/tty_ioctl.c:348
   set_termios+0x566/0x710 drivers/tty/tty_ioctl.c:516
   tty_mode_ioctl+0x4a6/0x7d0 drivers/tty/tty_ioctl.c:-1
   tty_ioctl+0x9c5/0xde0 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


stack backtrace:
CPU: 0 UID: 0 PID: 9658 Comm: syz.7.12181 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 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+0x2a94/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
 _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
 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+0x26/0x50 drivers/tty/tty_io.c:794
 n_tty_set_termios+0xa7c/0x10a0 drivers/tty/n_tty.c:1848
 tty_set_termios+0xdb3/0x1800 drivers/tty/tty_ioctl.c:348
 set_termios+0x566/0x710 drivers/tty/tty_ioctl.c:516
 tty_mode_ioctl+0x4a6/0x7d0 drivers/tty/tty_ioctl.c:-1
 tty_ioctl+0x9c5/0xde0 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f477679c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f477769c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4776a16090 RCX: 00007f477679c819
RDX: 0000200000000140 RSI: 0000000000005402 RDI: 0000000000000004
RBP: 00007f4776832c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4776a16128 R14: 00007f4776a16090 R15: 00007f4776b3fa48
 </TASK>