syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.1.6046/27470 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff888057a30440 (&tty->flow.lock){....}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
ffff888057a30440 (&tty->flow.lock){....}-{3:3}, at: stop_tty+0x2f/0x140 drivers/tty/tty_io.c:765

and this task is already holding:
ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: class_spinlock_constructor include/linux/spinlock.h:587 [inline]
ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: kbd_event+0xd6/0x4080 drivers/tty/vt/keyboard.c:1510
which would create a new lock dependency:
 (kbd_event_lock){..-.}-{3:3} -> (&tty->flow.lock){....}-{3:3}

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

... which became SOFTIRQ-irq-safe at:
  lock_acquire+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+0xd6/0x4080 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+0x84/0xc0 drivers/input/input.c:396
  rc_keydown+0x62/0x1e0 drivers/media/rc/rc-main.c:856
  imon_incoming_packet+0x1ecb/0x31c0 drivers/media/rc/imon.c:1677
  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_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5945
  lock_is_held include/linux/lockdep.h:249 [inline]
  __might_resched+0x86/0x4d0 kernel/sched/core.c:9119
  __wait_for_common+0xa6/0x690 kernel/sched/completion.c:116
  wait_for_common kernel/sched/completion.c:132 [inline]
  wait_for_completion_interruptible+0x1f/0x40 kernel/sched/completion.c:221
  raw_process_ep_io+0x609/0xd90 drivers/usb/gadget/legacy/raw_gadget.c:1122
  raw_ioctl_ep_write drivers/usb/gadget/legacy/raw_gadget.c:1153 [inline]
  raw_ioctl+0x252c/0x41c0 drivers/usb/gadget/legacy/raw_gadget.c:1325
  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

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:1679
  do_wait+0x1e7/0x510 kernel/exit.c:1723
  kernel_wait+0xd6/0x1c0 kernel/exit.c:1899
  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:3288 [inline]
  process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
  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 ***

5 locks held by syz.1.6046/27470:
 #0: ffff88802c101110 (&evdev->mutex){+.+.}-{4:4}, at: evdev_write+0x1ae/0x4c0 drivers/input/evdev.c:511
 #1: ffff88802c013230 (&dev->event_lock#2){..-.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
 #1: ffff88802c013230 (&dev->event_lock#2){..-.}-{3:3}, at: input_inject_event+0xa4/0x330 drivers/input/input.c:419
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: input_inject_event+0xb5/0x330 drivers/input/input.c:420
 #3: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #3: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
 #3: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: input_pass_values+0x8d/0x890 drivers/input/input.c:119
 #4: ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #4: ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: class_spinlock_constructor include/linux/spinlock.h:587 [inline]
 #4: ffffffff8f200ad8 (kbd_event_lock){..-.}-{3:3}, at: kbd_event+0xd6/0x4080 drivers/tty/vt/keyboard.c:1510

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+0xd6/0x4080 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+0x84/0xc0 drivers/input/input.c:396
                    rc_keydown+0x62/0x1e0 drivers/media/rc/rc-main.c:856
                    imon_incoming_packet+0x1ecb/0x31c0 drivers/media/rc/imon.c:1677
                    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_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5945
                    lock_is_held include/linux/lockdep.h:249 [inline]
                    __might_resched+0x86/0x4d0 kernel/sched/core.c:9119
                    __wait_for_common+0xa6/0x690 kernel/sched/completion.c:116
                    wait_for_common kernel/sched/completion.c:132 [inline]
                    wait_for_completion_interruptible+0x1f/0x40 kernel/sched/completion.c:221
                    raw_process_ep_io+0x609/0xd90 drivers/usb/gadget/legacy/raw_gadget.c:1122
                    raw_ioctl_ep_write drivers/usb/gadget/legacy/raw_gadget.c:1153 [inline]
                    raw_ioctl+0x252c/0x41c0 drivers/usb/gadget/legacy/raw_gadget.c:1325
                    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
   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:2126
                   reset_vc+0x68/0x1b0 drivers/tty/vt/vt_ioctl.c:966
                   vc_init+0x70/0x4a0 drivers/tty/vt/vt.c:3747
                   con_init+0x377/0x6a0 drivers/tty/vt/vt.c:3813
                   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: [<ffffffff8f200ad8>] kbd_event_lock+0x18/0xa0 keyboard.c:-1

the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
   -> (tasklist_lock){.+.+}-{3:3} {
      HARDIRQ-ON-R at:
                          lock_acquire+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:1679
                          do_wait+0x1e7/0x510 kernel/exit.c:1723
                          kernel_wait+0xd6/0x1c0 kernel/exit.c:1899
                          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:3288 [inline]
                          process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
                          worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
                          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:1679
                          do_wait+0x1e7/0x510 kernel/exit.c:1723
                          kernel_wait+0xd6/0x1c0 kernel/exit.c:1899
                          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:3288 [inline]
                          process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
                          worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
                          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:2412
                         kernel_clone+0x284/0x8f0 kernel/fork.c:2714
                         user_mode_thread+0x110/0x180 kernel/fork.c:2790
                         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:1679
                              do_wait+0x1e7/0x510 kernel/exit.c:1723
                              kernel_wait+0xd6/0x1c0 kernel/exit.c:1899
                              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:3288 [inline]
                              process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
                              worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
                              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_sendmsg net/socket.c:2784 [inline]
   __do_sys_sendmsg net/socket.c:2789 [inline]
   __se_sys_sendmsg net/socket.c:2787 [inline]
   __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787
   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
                        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/0x5450 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
                       __f_setown+0x67/0x370 fs/fcntl.c:136
                       f_setown+0x23a/0x300 fs/fcntl.c:183
                       sock_ioctl+0x615/0x7f0 net/socket.c:1375
                       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
     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
                            kill_fasync_rcu fs/fcntl.c:1144 [inline]
                            kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159
                            sock_wake_async+0x137/0x160 net/socket.c:-1
                            sk_wake_async+0x189/0x280 include/net/sock.h:2585
                            tcp_rcv_state_process+0x1e95/0x48f0 net/ipv4/tcp_input.c:7239
                            tcp_v4_do_rcv+0x649/0x13c0 net/ipv4/tcp_ipv4.c:1875
                            sk_backlog_rcv include/net/sock.h:1190 [inline]
                            __release_sock+0x265/0x3a0 net/core/sock.c:3216
                            release_sock+0x190/0x260 net/core/sock.c:3815
                            inet_wait_for_connect net/ipv4/af_inet.c:616 [inline]
                            __inet_stream_connect+0x85d/0xdd0 net/ipv4/af_inet.c:710
                            tcp_sendmsg_fastopen+0x3a7/0x5e0 net/ipv4/tcp.c:1089
                            tcp_sendmsg_locked+0x4b6f/0x5450 net/ipv4/tcp.c:1185
                            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
   }
   ... key      at: [<ffffffff9a5077c0>] 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
   sock_wake_async+0x137/0x160 net/socket.c:-1
   sk_wake_async+0x189/0x280 include/net/sock.h:2585
   tcp_rcv_state_process+0x1e95/0x48f0 net/ipv4/tcp_input.c:7239
   tcp_v4_do_rcv+0x649/0x13c0 net/ipv4/tcp_ipv4.c:1875
   sk_backlog_rcv include/net/sock.h:1190 [inline]
   __release_sock+0x265/0x3a0 net/core/sock.c:3216
   release_sock+0x190/0x260 net/core/sock.c:3815
   inet_wait_for_connect net/ipv4/af_inet.c:616 [inline]
   __inet_stream_connect+0x85d/0xdd0 net/ipv4/af_inet.c:710
   tcp_sendmsg_fastopen+0x3a7/0x5e0 net/ipv4/tcp.c:1089
   tcp_sendmsg_locked+0x4b6f/0x5450 net/ipv4/tcp.c:1185
   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

 -> (&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/0x5450 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
                     pipe_fasync+0xa9/0x1e0 fs/pipe.c:756
                     __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:328 [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
                          anon_pipe_write+0x728/0x1480 fs/pipe.c:572
                          fifo_pipe_write+0x25/0x4b0 fs/pipe.c:606
                          do_iter_readv_writev+0x619/0x8c0 fs/read_write.c:-1
                          vfs_writev+0x33c/0x990 fs/read_write.c:1059
                          do_writev+0x154/0x2e0 fs/read_write.c:1105
                          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: [<ffffffff9a5077e0>] 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 drivers/tty/tty_io.c:794 [inline]
   tty_send_xchar+0x1cf/0x4b0 drivers/tty/tty_io.c:1153
   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

-> (&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: [<ffffffff9a7e7380>] 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:1497 [inline]
   kbd_event+0x2e80/0x4080 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+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


stack backtrace:
CPU: 1 UID: 0 PID: 27470 Comm: syz.1.6046 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_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:1497 [inline]
 kbd_event+0x2e80/0x4080 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+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
RIP: 0033:0x7f0b3899c819
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:00007f0b397bd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0b38c15fa0 RCX: 00007f0b3899c819
RDX: 0000000000002250 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007f0b38a32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0b38c16038 R14: 00007f0b38c15fa0 R15: 00007f0b38d3fa48
 </TASK>