syzbot

futex_wake_op: syz.7.7006 tries to shift op by 144; fix this program
=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.7.7006/25610 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8e00c058 (tasklist_lock){.+.+}-{3:3}, at: send_sigurg+0x12b/0x420 fs/fcntl.c:978

and this task is already holding:
ffff88802f061d20 (&f_owner->lock){....}-{3:3}, at: send_sigurg+0x55/0x420 fs/fcntl.c:962
which would create a new lock dependency:
 (&f_owner->lock){....}-{3:3} -> (tasklist_lock){.+.+}-{3:3}

but this new dependency connects a SOFTIRQ-irq-safe lock:
 (&tty->flow.lock){..-.}-{3:3}

... which became SOFTIRQ-irq-safe 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]
  stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765
  kbd_keycode drivers/tty/vt/keyboard.c:1497 [inline]
  kbd_event+0x2b9f/0x3fa0 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_event+0x89/0xe0 drivers/input/input.c:396
  input_sync include/linux/input.h:464 [inline]
  hidinput_report_event+0xa1/0x100 drivers/hid/hid-input.c:1764
  hid_report_raw_event+0x148b/0x1720 drivers/hid/hid-core.c:2081
  __hid_input_report drivers/hid/hid-core.c:2144 [inline]
  hid_input_report+0x44b/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:1661
  dummy_timer+0x85f/0x45b0 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:626
  __do_softirq kernel/softirq.c:660 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
  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+0x13/0x20 arch/x86/kernel/paravirt.c:81
  arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
  default_idle+0x13/0x20 arch/x86/kernel/process.c:767
  default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
  cpuidle_idle_call kernel/sched/idle.c:191 [inline]
  do_idle+0x1ea/0x520 kernel/sched/idle.c:332
  cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
  start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
  common_startup_64+0x13e/0x147

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:1672
  do_wait+0x1e8/0x4f0 kernel/exit.c:1716
  kernel_wait+0xab/0x170 kernel/exit.c:1892
  call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
  call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
  process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
  process_scheduled_works kernel/workqueue.c:3362 [inline]
  worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
  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:
  &tty->flow.lock --> &f_owner->lock --> tasklist_lock

 Possible interrupt unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by syz.7.7006/25610:
 #0: ffff88807d3fb2a0 (&u->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #0: ffff88807d3fb2a0 (&u->lock){+.+.}-{3:3}, at: queue_oob+0x1b0/0x4f0 net/unix/af_unix.c:2336
 #1: ffff88802f061d20 (&f_owner->lock){....}-{3:3}, at: send_sigurg+0x55/0x420 fs/fcntl.c:962

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
  -> (&tty->flow.lock){..-.}-{3:3} {
     IN-SOFTIRQ-W 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]
                        stop_tty+0x2f/0x150 drivers/tty/tty_io.c:765
                        kbd_keycode drivers/tty/vt/keyboard.c:1497 [inline]
                        kbd_event+0x2b9f/0x3fa0 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_event+0x89/0xe0 drivers/input/input.c:396
                        input_sync include/linux/input.h:464 [inline]
                        hidinput_report_event+0xa1/0x100 drivers/hid/hid-input.c:1764
                        hid_report_raw_event+0x148b/0x1720 drivers/hid/hid-core.c:2081
                        __hid_input_report drivers/hid/hid-core.c:2144 [inline]
                        hid_input_report+0x44b/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:1661
                        dummy_timer+0x85f/0x45b0 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:626
                        __do_softirq kernel/softirq.c:660 [inline]
                        invoke_softirq kernel/softirq.c:496 [inline]
                        __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727
                        irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
                        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+0x13/0x20 arch/x86/kernel/paravirt.c:81
                        arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
                        default_idle+0x13/0x20 arch/x86/kernel/process.c:767
                        default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
                        cpuidle_idle_call kernel/sched/idle.c:191 [inline]
                        do_idle+0x1ea/0x520 kernel/sched/idle.c:332
                        cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
                        start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
                        common_startup_64+0x13e/0x147
     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/0x10c0 drivers/tty/n_tty.c:1848
                       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: [<ffffffff9a040080>] alloc_tty_struct.__key.35+0x0/0x20
 -> (&new->fa_lock){....}-{3:3} {
    INITIAL USE at:
                     lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
                     _raw_write_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:326
                     fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012
                     sock_fasync+0x85/0xf0 net/socket.c:1495
                     __fput+0x8a2/0xa70 fs/file_table.c:465
                     task_work_run+0x1d4/0x260 kernel/task_work.c:233
                     resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
                     __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
                     exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
                     __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
                     syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
                     syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
                     syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
                     do_syscall_64+0x2d0/0xf80 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
                          sock_wake_async+0x137/0x160 net/socket.c:-1
                          sk_wake_async+0x189/0x280 include/net/sock.h:2562
                          tcp_rcv_state_process+0x1d9d/0x4520 net/ipv4/tcp_input.c:7062
                          tcp_v4_do_rcv+0x6bb/0x1430 net/ipv4/tcp_ipv4.c:1904
                          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
                          inet_wait_for_connect net/ipv4/af_inet.c:611 [inline]
                          __inet_stream_connect+0x8df/0xe70 net/ipv4/af_inet.c:705
                          inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:750
                          __sys_connect_file net/socket.c:2104 [inline]
                          __sys_connect+0x316/0x440 net/socket.c:2123
                          __do_sys_connect net/socket.c:2129 [inline]
                          __se_sys_connect net/socket.c:2126 [inline]
                          __x64_sys_connect+0x7a/0x90 net/socket.c:2126
                          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: [<ffffffff99d61c80>] 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/0x10c0 drivers/tty/n_tty.c:1848
   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

-> (&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
                   __tty_fasync drivers/tty/tty_io.c:2237 [inline]
                   tty_fasync+0x2dc/0x350 drivers/tty/tty_io.c:2252
                   ioctl_fioasync fs/ioctl.c:378 [inline]
                   do_vfs_ioctl+0x1064/0x1430 fs/ioctl.c:511
                   __do_sys_ioctl fs/ioctl.c:595 [inline]
                   __se_sys_ioctl+0x82/0x170 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
   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
                        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/0x10c0 drivers/tty/n_tty.c:1848
                        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: [<ffffffff99d61c60>] 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
   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/0x10c0 drivers/tty/n_tty.c:1848
   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


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:1672
                    do_wait+0x1e8/0x4f0 kernel/exit.c:1716
                    kernel_wait+0xab/0x170 kernel/exit.c:1892
                    call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                    call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                    process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
                    process_scheduled_works kernel/workqueue.c:3362 [inline]
                    worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
                    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:1672
                    do_wait+0x1e8/0x4f0 kernel/exit.c:1716
                    kernel_wait+0xab/0x170 kernel/exit.c:1892
                    call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                    call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                    process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
                    process_scheduled_works kernel/workqueue.c:3362 [inline]
                    worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
                    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:2367
                   kernel_clone+0x21e/0x820 kernel/fork.c:2651
                   user_mode_thread+0xdd/0x140 kernel/fork.c:2727
                   rest_init+0x23/0x300 init/main.c:722
                   start_kernel+0x3a7/0x400 init/main.c:1206
                   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:1672
                        do_wait+0x1e8/0x4f0 kernel/exit.c:1716
                        kernel_wait+0xab/0x170 kernel/exit.c:1892
                        call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                        call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                        process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
                        process_scheduled_works kernel/workqueue.c:3362 [inline]
                        worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
                        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: [<ffffffff8e00c058>] 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
   queue_oob+0x420/0x4f0 net/unix/af_unix.c:2357
   unix_stream_sendmsg+0xc32/0xde0 net/unix/af_unix.c:2491
   sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
   __sock_sendmsg net/socket.c:752 [inline]
   ____sys_sendmsg+0x577/0x880 net/socket.c:2610
   ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
   __sys_sendmmsg+0x227/0x430 net/socket.c:2753
   __do_sys_sendmmsg net/socket.c:2780 [inline]
   __se_sys_sendmmsg net/socket.c:2777 [inline]
   __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2777
   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: 25610 Comm: syz.7.7006 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 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
 queue_oob+0x420/0x4f0 net/unix/af_unix.c:2357
 unix_stream_sendmsg+0xc32/0xde0 net/unix/af_unix.c:2491
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 ____sys_sendmsg+0x577/0x880 net/socket.c:2610
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
 __sys_sendmmsg+0x227/0x430 net/socket.c:2753
 __do_sys_sendmmsg net/socket.c:2780 [inline]
 __se_sys_sendmmsg net/socket.c:2777 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2777
 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: 0033:0x7fb62c58f749
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:00007fb62d47a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fb62c7e5fa0 RCX: 00007fb62c58f749
RDX: 0000000000000001 RSI: 0000200000006c40 RDI: 0000000000000005
RBP: 00007fb62c613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000040015 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb62c7e6038 R14: 00007fb62c7e5fa0 R15: 00007ffd9805c8e8
 </TASK>