syzbot


possible deadlock in kbd_event

Status: upstream: reported on 2025/10/14 00:10
Subsystems: serial kernfs
[Documentation on labels]
Reported-by: syzbot+781c8bb5e4d62cc883d3@syzkaller.appspotmail.com
First crash: 58d, last: 2d10h
Discussions (4)
Title Replies (including bot) Last reply
[syzbot] Monthly serial report (Nov 2025) 0 (1) 2025/11/27 12:43
[syzbot] Monthly kernfs report (Nov 2025) 0 (1) 2025/11/25 08:46
[syzbot] Monthly serial report (Oct 2025) 0 (1) 2025/10/27 05:54
[syzbot] [serial?] possible deadlock in kbd_event 0 (1) 2025/10/14 00:10

Sample crash report:
=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.0.5217/23403 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff88805422fa98 (&new->fa_lock){...-}-{3:3}, at: kill_fasync_rcu fs/fcntl.c:1135 [inline]
ffff88805422fa98 (&new->fa_lock){...-}-{3:3}, at: kill_fasync+0x199/0x4d0 fs/fcntl.c:1159

and this task is already holding:
ffff8880627ad468 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
ffff8880627ad468 (&tty->flow.lock){....}-{3:3}, at: start_tty+0x20/0x70 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+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+0x1404/0x1dd0 drivers/hid/hid-input.c:1745
  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
  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
  _raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
  hrtimer_start_expires include/linux/hrtimer.h:273 [inline]
  hrtimer_sleeper_start_expires kernel/time/hrtimer.c:2039 [inline]
  do_nanosleep+0x18c/0x610 kernel/time/hrtimer.c:2113
  hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2163
  __do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
  __se_sys_clock_nanosleep+0x339/0x390 kernel/time/posix-timers.c:1375
  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:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  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 ***

6 locks held by syz.0.5217/23403:
 #0: ffff8880627ad0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffff8880627ad2e8 (&tty->termios_rwsem/1){++++}-{4:4}, at: tty_set_termios+0x138/0x17e0 drivers/tty/tty_ioctl.c:333
 #2: ffff8880627ad0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #3: ffff8880627ad468 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline]
 #3: ffff8880627ad468 (&tty->flow.lock){....}-{3:3}, at: start_tty+0x20/0x70 drivers/tty/tty_io.c:793
 #4: ffff8880627ad0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #5: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #5: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #5: ffffffff8df41cc0 (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+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+0x1404/0x1dd0 drivers/hid/hid-input.c:1745
                      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
                      __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
                      _raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
                      hrtimer_start_expires include/linux/hrtimer.h:273 [inline]
                      hrtimer_sleeper_start_expires kernel/time/hrtimer.c:2039 [inline]
                      do_nanosleep+0x18c/0x610 kernel/time/hrtimer.c:2113
                      hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2163
                      __do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
                      __se_sys_clock_nanosleep+0x339/0x390 kernel/time/posix-timers.c:1375
                      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:4364
                     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: [<ffffffff8e775378>] kbd_event_lock+0x18/0xa0 keyboard.c:-1
-> (&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: [<ffffffff99b97100>] 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


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:3257 [inline]
                        process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
                        worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
                        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:3257 [inline]
                        process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
                        worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
                        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:2324
                       kernel_clone+0x21e/0x820 kernel/fork.c:2608
                       user_mode_thread+0xdd/0x140 kernel/fork.c:2684
                       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:3257 [inline]
                            process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
                            worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
                            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_sigurg+0x12b/0x420 fs/fcntl.c:978
   sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3669
   tcp_check_urg+0x200/0x760 net/ipv4/tcp_input.c:6030
   tcp_urg+0x164/0x3f0 net/ipv4/tcp_input.c:6071
   tcp_rcv_established+0xf4c/0x2580 net/ipv4/tcp_input.c:6471
   tcp_v4_do_rcv+0xa90/0x1430 net/ipv4/tcp_ipv4.c:1881
   sk_backlog_rcv include/net/sock.h:1177 [inline]
   __release_sock+0x265/0x3a0 net/core/sock.c:3213
   release_sock+0x5f/0x1f0 net/core/sock.c:3795
   tcp_sendmsg+0x39/0x50 net/ipv4/tcp.c:1413
   sock_sendmsg_nosec net/socket.c:718 [inline]
   __sock_sendmsg+0xe5/0x270 net/socket.c:733
   ____sys_sendmsg+0x505/0x820 net/socket.c:2583
   ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2637
   __sys_sendmsg net/socket.c:2669 [inline]
   __do_sys_sendmsg net/socket.c:2674 [inline]
   __se_sys_sendmsg net/socket.c:2672 [inline]
   __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2672
   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
                          lease_break_callback+0x26/0x30 fs/locks.c:558
                          __break_lease+0x730/0x1620 fs/locks.c:1598
                          break_lease include/linux/filelock.h:476 [inline]
                          do_dentry_open+0x73a/0x1420 fs/open.c:953
                          vfs_open+0x3b/0x340 fs/open.c:1094
                          do_open fs/namei.c:4628 [inline]
                          path_openat+0x340e/0x3dd0 fs/namei.c:4787
                          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
  }
  ... key      at: [<ffffffff998b9b60>] 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
   lease_break_callback+0x26/0x30 fs/locks.c:558
   __break_lease+0x730/0x1620 fs/locks.c:1598
   break_lease include/linux/filelock.h:476 [inline]
   do_dentry_open+0x73a/0x1420 fs/open.c:953
   vfs_open+0x3b/0x340 fs/open.c:1094
   do_open fs/namei.c:4628 [inline]
   path_openat+0x340e/0x3dd0 fs/namei.c:4787
   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

-> (&new->fa_lock){...-}-{3:3} {
   IN-SOFTIRQ-R 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
                    sock_wake_async+0x137/0x160 net/socket.c:-1
                    sk_wake_async_rcu include/net/sock.h:2570 [inline]
                    sock_def_readable+0x3c1/0x530 net/core/sock.c:3613
                    tcp_data_queue+0x201e/0x6590 net/ipv4/tcp_input.c:5461
                    tcp_rcv_established+0xf57/0x2580 net/ipv4/tcp_input.c:6474
                    tcp_v4_do_rcv+0xa90/0x1430 net/ipv4/tcp_ipv4.c:1881
                    tcp_v4_rcv+0x2675/0x2f20 net/ipv4/tcp_ipv4.c:2324
                    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+0x30c/0x3a0 include/linux/netfilter.h:318
                    NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
                    __netif_receive_skb_one_core net/core/dev.c:6137 [inline]
                    __netif_receive_skb+0x143/0x380 net/core/dev.c:6250
                    process_backlog+0x622/0x1500 net/core/dev.c:6602
                    __napi_poll+0xae/0x320 net/core/dev.c:7666
                    napi_poll net/core/dev.c:7729 [inline]
                    net_rx_action+0x672/0xe50 net/core/dev.c:7881
                    handle_softirqs+0x27d/0x850 kernel/softirq.c:622
                    do_softirq+0xec/0x180 kernel/softirq.c:523
                    __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450
                    sk_stream_wait_memory+0x71f/0xf70 net/core/stream.c:149
                    tcp_sendmsg_locked+0x1dfb/0x5520 net/ipv4/tcp.c:1365
                    tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1412
                    sock_sendmsg_nosec net/socket.c:718 [inline]
                    __sock_sendmsg+0x19c/0x270 net/socket.c:733
                    __sys_sendto+0x3bd/0x520 net/socket.c:2197
                    __do_sys_sendto net/socket.c:2204 [inline]
                    __se_sys_sendto net/socket.c:2200 [inline]
                    __x64_sys_sendto+0xde/0x100 net/socket.c:2200
                    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_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
                   lease_modify+0x1ca/0x3c0 fs/locks.c:1455
                   locks_remove_lease fs/locks.c:2726 [inline]
                   locks_remove_file+0x4bf/0xea0 fs/locks.c:2751
                   __fput+0x3ab/0xa70 fs/file_table.c:460
                   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
                        lease_break_callback+0x26/0x30 fs/locks.c:558
                        __break_lease+0x730/0x1620 fs/locks.c:1598
                        break_lease include/linux/filelock.h:476 [inline]
                        do_dentry_open+0x73a/0x1420 fs/open.c:953
                        vfs_open+0x3b/0x340 fs/open.c:1094
                        do_open fs/namei.c:4628 [inline]
                        path_openat+0x340e/0x3dd0 fs/namei.c:4787
                        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
 }
 ... key      at: [<ffffffff998b9b80>] 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


stack backtrace:
CPU: 0 UID: 0 PID: 23403 Comm: syz.0.5217 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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_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
RIP: 0033:0x7fc5c878f749
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:00007fc5c963e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc5c89e6090 RCX: 00007fc5c878f749
RDX: 0000200000000140 RSI: 0000000000005402 RDI: 0000000000000004
RBP: 00007fc5c8813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5c89e6128 R14: 00007fc5c89e6090 R15: 00007fc5c8b0fa28
 </TASK>

Crashes (111):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 13:37 upstream 2061f18ad76e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/05 00:13 upstream aa833fc394ba d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/04 10:45 upstream 559e608c4655 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/03 21:22 upstream a619fe35ab41 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/03 12:08 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/03 04:54 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/02 15:16 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/12/02 01:09 upstream 1d18101a644e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/30 06:21 upstream 6bda50f4333f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/30 01:34 upstream 6bda50f4333f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/28 21:22 upstream 6cf62f0174de d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/28 08:05 upstream e538109ac71d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/27 04:11 upstream 4941a17751c9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/21 14:35 upstream fd95357fd8c6 c31c1b0b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/20 13:29 upstream 23cb64fb7625 280ea308 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/20 03:28 upstream 8b690556d8fe 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/19 12:58 upstream 8b690556d8fe 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/19 08:38 upstream 5bebe8de1926 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/19 03:00 upstream 5bebe8de1926 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/18 20:32 upstream 5bebe8de1926 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/18 03:06 upstream e7c375b18160 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/16 08:16 upstream f824272b6e3f f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/15 20:39 upstream f824272b6e3f f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/15 17:15 upstream 7a0892d2836e f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/13 18:05 upstream 2ccec5944606 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/13 04:26 upstream e927c520e1ba 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/09 14:29 upstream 439fc29dfd3b 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/09 14:29 upstream 439fc29dfd3b 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/08 19:27 upstream e811c33b1f13 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/06 02:00 upstream 1c353dc8d962 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/05 13:53 upstream 1c353dc8d962 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/04 23:27 upstream 17d85f33a83b a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/04 01:08 upstream 8bb886cb8f3a 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/02 23:05 upstream 6146a0f1dfae 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/02 09:28 upstream 691d401c7e0e 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/01 17:33 upstream ba36dd5ee6fd 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/01 07:42 upstream ba36dd5ee6fd 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/01 02:03 upstream 58fdd8484c05 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/31 07:13 upstream e53642b87a4f 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/30 22:03 upstream e53642b87a4f 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/30 05:24 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/30 02:33 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/29 13:28 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/28 06:20 upstream fd57572253bc fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/28 06:16 upstream fd57572253bc fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/27 16:39 upstream dcb6fa37fd7b fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/13 18:09 upstream 3a8660878839 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/10/10 00:07 upstream 18a7e218cfcd 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in kbd_event
2025/11/26 15:23 upstream 30f09200cc4a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 possible deadlock in kbd_event
2025/11/22 12:56 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 possible deadlock in kbd_event
2025/12/05 01:33 linux-next bc04acf4aeca d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in kbd_event
2025/10/30 08:37 linux-next 131f3d9446a6 fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in kbd_event
2025/10/10 07:40 linux-next 0b2f041c47ac ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in kbd_event
* Struck through repros no longer work on HEAD.