syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.5.9286/7460 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff8880741b6018 (&new->fa_lock){....}-{3:3}, at: kill_fasync_rcu fs/fcntl.c:1135 [inline]
ffff8880741b6018 (&new->fa_lock){....}-{3:3}, at: kill_fasync+0x199/0x4d0 fs/fcntl.c:1159

and this task is already holding:
ffff88806ba3e468 (&tty->flow.lock){....}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:371 [inline]
ffff88806ba3e468 (&tty->flow.lock){....}-{3:3}, at: n_tty_ioctl_helper+0xe0/0x4d0 drivers/tty/tty_ioctl.c:956
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+0xf0/0x2e0 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:154
  spin_lock include/linux/spinlock.h:341 [inline]
  class_spinlock_constructor include/linux/spinlock.h:586 [inline]
  kbd_event+0xd6/0x40d0 drivers/tty/vt/keyboard.c:1510
  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+0x89/0xe0 drivers/input/input.c:396
  input_sync include/linux/input.h:464 [inline]
  creative_sb0540_raw_event+0x38e/0x430 drivers/hid/hid-creative-sb0540.c:179
  __hid_input_report drivers/hid/hid-core.c:2139 [inline]
  hid_input_report+0x41d/0x580 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:1657
  dummy_timer+0xbbd/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1995
  __run_hrtimer kernel/time/hrtimer.c:1785 [inline]
  __hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849
  hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1866
  handle_softirqs+0x22a/0x870 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0x5f/0x150 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
  native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
  pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:62
  arch_safe_halt arch/x86/kernel/process.c:766 [inline]
  default_idle+0x9/0x20 arch/x86/kernel/process.c:767
  default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
  cpuidle_idle_call kernel/sched/idle.c:191 [inline]
  do_idle+0x1ba/0x5d0 kernel/sched/idle.c:341
  cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:439
  rest_init+0x2de/0x300 init/main.c:760
  start_kernel+0x385/0x3d0 init/main.c:1210
  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

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

... which became SOFTIRQ-irq-unsafe at:
...
  lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
  __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
  _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
  __do_wait+0xde/0x740 kernel/exit.c:1678
  do_wait+0x1e7/0x540 kernel/exit.c:1722
  kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
  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:3276 [inline]
  process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
  kthread+0x388/0x470 kernel/kthread.c:436
  ret_from_fork+0x51e/0xb90 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 ***

4 locks held by syz.5.9286/7460:
 #0: ffff88806ba3e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffff88806ba3e468 (&tty->flow.lock){....}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:371 [inline]
 #1: ffff88806ba3e468 (&tty->flow.lock){....}-{3:3}, at: n_tty_ioctl_helper+0xe0/0x4d0 drivers/tty/tty_ioctl.c:956
 #2: ffff88806ba3e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #3: ffffffff8e75e460 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #3: ffffffff8e75e460 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #3: ffffffff8e75e460 (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+0xf0/0x2e0 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:154
                      spin_lock include/linux/spinlock.h:341 [inline]
                      class_spinlock_constructor include/linux/spinlock.h:586 [inline]
                      kbd_event+0xd6/0x40d0 drivers/tty/vt/keyboard.c:1510
                      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+0x89/0xe0 drivers/input/input.c:396
                      input_sync include/linux/input.h:464 [inline]
                      creative_sb0540_raw_event+0x38e/0x430 drivers/hid/hid-creative-sb0540.c:179
                      __hid_input_report drivers/hid/hid-core.c:2139 [inline]
                      hid_input_report+0x41d/0x580 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:1657
                      dummy_timer+0xbbd/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1995
                      __run_hrtimer kernel/time/hrtimer.c:1785 [inline]
                      __hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849
                      hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1866
                      handle_softirqs+0x22a/0x870 kernel/softirq.c:622
                      __do_softirq kernel/softirq.c:656 [inline]
                      invoke_softirq kernel/softirq.c:496 [inline]
                      __irq_exit_rcu+0x5f/0x150 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
                      native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
                      pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:62
                      arch_safe_halt arch/x86/kernel/process.c:766 [inline]
                      default_idle+0x9/0x20 arch/x86/kernel/process.c:767
                      default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
                      cpuidle_idle_call kernel/sched/idle.c:191 [inline]
                      do_idle+0x1ba/0x5d0 kernel/sched/idle.c:341
                      cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:439
                      rest_init+0x2de/0x300 init/main.c:760
                      start_kernel+0x385/0x3d0 init/main.c:1210
                      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 USE at:
                     lock_acquire+0xf0/0x2e0 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:162
                     class_spinlock_irqsave_constructor include/linux/spinlock.h:618 [inline]
                     vt_reset_unicode+0x2b/0x1a0 drivers/tty/vt/keyboard.c:2126
                     reset_vc+0x68/0x1b0 drivers/tty/vt/vt_ioctl.c:966
                     vc_init+0x70/0x4a0 drivers/tty/vt/vt.c:3721
                     con_init+0x377/0x6a0 drivers/tty/vt/vt.c:3787
                     console_init+0x10b/0x4d0 kernel/printk/printk.c:4407
                     start_kernel+0x22b/0x3d0 init/main.c:1147
                     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: [<ffffffff8effc0f8>] kbd_event_lock+0x18/0xa0 keyboard.c:-1
-> (&tty->flow.lock){....}-{3:3} {
   INITIAL USE at:
                   lock_acquire+0xf0/0x2e0 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:162
                   class_spinlock_irqsave_constructor include/linux/spinlock.h:618 [inline]
                   start_tty+0x20/0x70 drivers/tty/tty_io.c:793
                   n_tty_set_termios+0xa7c/0x10c0 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff9a5cb6a0>] 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:162
   class_spinlock_irqsave_constructor include/linux/spinlock.h:618 [inline]
   stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765
   kbd_keycode drivers/tty/vt/keyboard.c:1497 [inline]
   kbd_event+0x2ec1/0x40d0 drivers/tty/vt/keyboard.c:1515
   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+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+0x14d/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+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                        __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                        _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                        __do_wait+0xde/0x740 kernel/exit.c:1678
                        do_wait+0x1e7/0x540 kernel/exit.c:1722
                        kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                        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:3276 [inline]
                        process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x51e/0xb90 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+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                        __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                        _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                        __do_wait+0xde/0x740 kernel/exit.c:1678
                        do_wait+0x1e7/0x540 kernel/exit.c:1722
                        kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                        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:3276 [inline]
                        process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
     INITIAL USE at:
                       lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                       __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                       _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                       copy_process+0x247a/0x3cf0 kernel/fork.c:2369
                       kernel_clone+0x248/0x8e0 kernel/fork.c:2654
                       user_mode_thread+0x110/0x180 kernel/fork.c:2730
                       rest_init+0x23/0x300 init/main.c:725
                       start_kernel+0x385/0x3d0 init/main.c:1210
                       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+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                            __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                            _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                            __do_wait+0xde/0x740 kernel/exit.c:1678
                            do_wait+0x1e7/0x540 kernel/exit.c:1722
                            kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                            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:3276 [inline]
                            process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
                            worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
                            kthread+0x388/0x470 kernel/kthread.c:436
                            ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
                            ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   }
   ... key      at: [<ffffffff8e40c058>] tasklist_lock+0x18/0x40
   ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:161 [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: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:4586 [inline]
   path_openat+0x15c2/0x3860 fs/namei.c:4827
   do_file_open+0x23e/0x4a0 fs/namei.c:4859
   do_sys_openat2+0x113/0x200 fs/open.c:1366
   do_sys_open fs/open.c:1372 [inline]
   __do_sys_open fs/open.c:1380 [inline]
   __se_sys_open fs/open.c:1376 [inline]
   __x64_sys_open+0x11e/0x150 fs/open.c:1376
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x14d/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+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                     _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                     __f_setown+0x67/0x370 fs/fcntl.c:136
                     f_setown_ex fs/fcntl.c:254 [inline]
                     do_fcntl+0x171c/0x1a20 fs/fcntl.c:520
                     __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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL READ USE at:
                          lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                          __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
                          _raw_read_lock_irqsave+0x48/0x60 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
                          lease_break_callback+0x26/0x30 fs/locks.c:577
                          __break_lease+0x81c/0x1e80 fs/locks.c:1657
                          break_deleg include/linux/filelock.h:504 [inline]
                          try_break_deleg include/linux/filelock.h:523 [inline]
                          vfs_create+0x39c/0x460 fs/namei.c:4173
                          filename_mknodat+0x3e8/0x660 fs/namei.c:5142
                          __do_sys_mknodat fs/namei.c:5173 [inline]
                          __se_sys_mknodat+0x3b/0x150 fs/namei.c:5169
                          do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                          do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                          entry_SYSCALL_64_after_hwframe+0x77/0x7f
  }
  ... key      at: [<ffffffff9a2ec1e0>] file_f_owner_allocate.__key+0x0/0x20
  ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
   _raw_read_lock_irqsave+0x48/0x60 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
   lease_break_callback+0x26/0x30 fs/locks.c:577
   __break_lease+0x81c/0x1e80 fs/locks.c:1657
   break_deleg include/linux/filelock.h:504 [inline]
   try_break_deleg include/linux/filelock.h:523 [inline]
   vfs_create+0x39c/0x460 fs/namei.c:4173
   filename_mknodat+0x3e8/0x660 fs/namei.c:5142
   __do_sys_mknodat fs/namei.c:5173 [inline]
   __se_sys_mknodat+0x3b/0x150 fs/namei.c:5169
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> (&new->fa_lock){....}-{3:3} {
   INITIAL USE at:
                   lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                   _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                   fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012
                   sock_fasync+0x85/0xf0 net/socket.c:1480
                   __fput+0x8a5/0xa70 fs/file_table.c:466
                   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:226 [inline]
                   syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
                   syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
                   do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL READ USE at:
                        lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
                        __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
                        _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:236
                        kill_fasync_rcu fs/fcntl.c:1135 [inline]
                        kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                        lease_break_callback+0x26/0x30 fs/locks.c:577
                        __break_lease+0x81c/0x1e80 fs/locks.c:1657
                        break_deleg include/linux/filelock.h:504 [inline]
                        try_break_deleg include/linux/filelock.h:523 [inline]
                        vfs_create+0x39c/0x460 fs/namei.c:4173
                        filename_mknodat+0x3e8/0x660 fs/namei.c:5142
                        __do_sys_mknodat fs/namei.c:5173 [inline]
                        __se_sys_mknodat+0x3b/0x150 fs/namei.c:5169
                        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                        do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                        entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff9a2ec200>] fasync_insert_entry.__key+0x0/0x20
 ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
   _raw_read_lock_irqsave+0x48/0x60 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
   n_tty_ioctl_helper+0x128/0x4d0 drivers/tty/tty_ioctl.c:959
   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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


stack backtrace:
CPU: 0 UID: 0 PID: 7460 Comm: syz.5.9286 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
 _raw_read_lock_irqsave+0x48/0x60 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
 n_tty_ioctl_helper+0x128/0x4d0 drivers/tty/tty_ioctl.c:959
 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdb9bf9c799
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:00007fdb9cea3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdb9c216270 RCX: 00007fdb9bf9c799
RDX: 0000000000000001 RSI: 000000000000540a RDI: 0000000000000008
RBP: 00007fdb9c032c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb9c216308 R14: 00007fdb9c216270 R15: 00007fdb9c33fa48
 </TASK>