syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.4.4396/22366 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8e60a058 (tasklist_lock){.+.+}-{3:3}, at: send_sigurg+0x12b/0x420 fs/fcntl.c:978

and this task is already holding:
ffff88803dfcf8a0 (&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:
 (&client->buffer_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]
  evdev_pass_values+0xb9/0xbd0 drivers/input/evdev.c:261
  evdev_events+0x1e6/0x340 drivers/input/evdev.c:306
  input_pass_values+0x288/0x890 drivers/input/input.c:128
  input_event_dispose+0x3e5/0x6b0 drivers/input/input.c:353
  input_event+0x84/0xc0 drivers/input/input.c:396
  hidinput_hid_event+0x143a/0x1ec0 drivers/hid/hid-input.c:1762
  hid_process_event+0x4be/0x620 drivers/hid/hid-core.c:1576
  hid_process_report drivers/hid/hid-core.c:1724 [inline]
  hid_report_raw_event+0xec2/0x1730 drivers/hid/hid-core.c:2082
  __hid_input_report drivers/hid/hid-core.c:2152 [inline]
  hid_input_report+0x44b/0x580 drivers/hid/hid-core.c:2174
  hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
  __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1657
  dummy_timer+0xbc0/0x4650 drivers/usb/gadget/udc/dummy_hcd.c:2005
  __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
  __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
  hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2011
  handle_softirqs+0x22a/0x840 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
  lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
  rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
  rcu_read_lock include/linux/rcupdate.h:838 [inline]
  class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
  unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
  arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
  stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
  __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
  kasan_kmalloc include/linux/kasan.h:263 [inline]
  __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419
  kmalloc_noprof include/linux/slab.h:950 [inline]
  kzalloc_noprof include/linux/slab.h:1188 [inline]
  kobject_uevent_env+0x28c/0x9e0 lib/kobject_uevent.c:543
  really_probe+0x789/0xaf0 drivers/base/dd.c:759
  __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
  driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
  __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
  bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
  __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
  device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
  bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
  device_add+0x7e9/0xbb0 drivers/base/core.c:3706
  hid_add_device+0x272/0x3e0 drivers/hid/hid-core.c:2964
  usbhid_probe+0xbab/0x1080 drivers/hid/usbhid/hid-core.c:1448
  usb_probe_interface+0x659/0xc70 drivers/usb/core/driver.c:396
  call_driver_probe drivers/base/dd.c:-1 [inline]
  really_probe+0x267/0xaf0 drivers/base/dd.c:709
  __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
  driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
  __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
  bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
  __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
  device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
  bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
  device_add+0x7e9/0xbb0 drivers/base/core.c:3706
  usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2268
  usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
  usb_probe_device+0x1c4/0x3b0 drivers/usb/core/driver.c:291
  call_driver_probe drivers/base/dd.c:-1 [inline]
  really_probe+0x267/0xaf0 drivers/base/dd.c:709
  __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
  driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
  __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
  bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
  __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
  device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
  bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
  device_add+0x7e9/0xbb0 drivers/base/core.c:3706
  usb_new_device+0xa08/0x16f0 drivers/usb/core/hub.c:2695
  hub_port_connect drivers/usb/core/hub.c:5567 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
  port_event drivers/usb/core/hub.c:5871 [inline]
  hub_event+0x2a1c/0x4f30 drivers/usb/core/hub.c:5953
  process_one_work kernel/workqueue.c:3302 [inline]
  process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
  kthread+0x388/0x470 kernel/kthread.c:436
  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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:1678
  do_wait+0x1e7/0x510 kernel/exit.c:1722
  kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
  call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
  call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
  process_one_work kernel/workqueue.c:3302 [inline]
  process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
  kthread+0x388/0x470 kernel/kthread.c:436
  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &client->buffer_lock --> &f_owner->lock --> tasklist_lock

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(tasklist_lock);
                               local_irq_disable();
                               lock(&client->buffer_lock);
                               lock(&f_owner->lock);
  <Interrupt>
    lock(&client->buffer_lock);

 *** DEADLOCK ***

2 locks held by syz.4.4396/22366:
 #0: ffff8880213297d0 (&u->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #0: ffff8880213297d0 (&u->lock){+.+.}-{3:3}, at: queue_oob+0x1b6/0x4f0 net/unix/af_unix.c:2347
 #1: ffff88803dfcf8a0 (&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:
  -> (&client->buffer_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]
                        evdev_pass_values+0xb9/0xbd0 drivers/input/evdev.c:261
                        evdev_events+0x1e6/0x340 drivers/input/evdev.c:306
                        input_pass_values+0x288/0x890 drivers/input/input.c:128
                        input_event_dispose+0x3e5/0x6b0 drivers/input/input.c:353
                        input_event+0x84/0xc0 drivers/input/input.c:396
                        hidinput_hid_event+0x143a/0x1ec0 drivers/hid/hid-input.c:1762
                        hid_process_event+0x4be/0x620 drivers/hid/hid-core.c:1576
                        hid_process_report drivers/hid/hid-core.c:1724 [inline]
                        hid_report_raw_event+0xec2/0x1730 drivers/hid/hid-core.c:2082
                        __hid_input_report drivers/hid/hid-core.c:2152 [inline]
                        hid_input_report+0x44b/0x580 drivers/hid/hid-core.c:2174
                        hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
                        __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1657
                        dummy_timer+0xbc0/0x4650 drivers/usb/gadget/udc/dummy_hcd.c:2005
                        __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
                        __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
                        hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2011
                        handle_softirqs+0x22a/0x840 kernel/softirq.c:622
                        __do_softirq kernel/softirq.c:656 [inline]
                        invoke_softirq kernel/softirq.c:496 [inline]
                        __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
                        irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
                        instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
                        sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
                        asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
                        lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
                        rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
                        rcu_read_lock include/linux/rcupdate.h:838 [inline]
                        class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
                        unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
                        arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
                        stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
                        kasan_save_stack mm/kasan/common.c:57 [inline]
                        kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
                        poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
                        __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
                        kasan_kmalloc include/linux/kasan.h:263 [inline]
                        __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419
                        kmalloc_noprof include/linux/slab.h:950 [inline]
                        kzalloc_noprof include/linux/slab.h:1188 [inline]
                        kobject_uevent_env+0x28c/0x9e0 lib/kobject_uevent.c:543
                        really_probe+0x789/0xaf0 drivers/base/dd.c:759
                        __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
                        driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
                        __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
                        bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
                        __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
                        device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
                        bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
                        device_add+0x7e9/0xbb0 drivers/base/core.c:3706
                        hid_add_device+0x272/0x3e0 drivers/hid/hid-core.c:2964
                        usbhid_probe+0xbab/0x1080 drivers/hid/usbhid/hid-core.c:1448
                        usb_probe_interface+0x659/0xc70 drivers/usb/core/driver.c:396
                        call_driver_probe drivers/base/dd.c:-1 [inline]
                        really_probe+0x267/0xaf0 drivers/base/dd.c:709
                        __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
                        driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
                        __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
                        bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
                        __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
                        device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
                        bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
                        device_add+0x7e9/0xbb0 drivers/base/core.c:3706
                        usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2268
                        usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
                        usb_probe_device+0x1c4/0x3b0 drivers/usb/core/driver.c:291
                        call_driver_probe drivers/base/dd.c:-1 [inline]
                        really_probe+0x267/0xaf0 drivers/base/dd.c:709
                        __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
                        driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
                        __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
                        bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
                        __device_attach+0x2c5/0x450 drivers/base/dd.c:1101
                        device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156
                        bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
                        device_add+0x7e9/0xbb0 drivers/base/core.c:3706
                        usb_new_device+0xa08/0x16f0 drivers/usb/core/hub.c:2695
                        hub_port_connect drivers/usb/core/hub.c:5567 [inline]
                        hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
                        port_event drivers/usb/core/hub.c:5871 [inline]
                        hub_event+0x2a1c/0x4f30 drivers/usb/core/hub.c:5953
                        process_one_work kernel/workqueue.c:3302 [inline]
                        process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
     INITIAL USE at:
                       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                       __raw_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]
                       evdev_pass_values+0xb9/0xbd0 drivers/input/evdev.c:261
                       evdev_events+0x1e6/0x340 drivers/input/evdev.c:306
                       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
   }
   ... key      at: [<ffffffff9a7e0840>] evdev_open.__key.27+0x0/0x20
 -> (&new->fa_lock){....}-{3:3} {
    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
                     lease_modify+0x4f7/0x6c0 fs/locks.c:1514
                     locks_remove_lease fs/locks.c:2773 [inline]
                     locks_remove_file+0x5f0/0xf70 fs/locks.c:2798
                     __fput+0x3ae/0xa60 fs/file_table.c:502
                     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+0xf3/0x4d0 kernel/entry/common.c:98
                     __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
                     syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
                     syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
                     do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
                     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL READ USE at:
                          lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                          __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
                          _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:240
                          kill_fasync_rcu fs/fcntl.c:1135 [inline]
                          kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                          wakeup_pipe_readers fs/splice.c:183 [inline]
                          splice_pipe_to_pipe fs/splice.c:1839 [inline]
                          do_splice+0x1028/0x1910 fs/splice.c:1326
                          __do_splice fs/splice.c:1431 [inline]
                          __do_sys_splice fs/splice.c:1634 [inline]
                          __se_sys_splice+0x353/0x490 fs/splice.c:1616
                          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: [<ffffffff9a4bf8a0>] 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
   __pass_event drivers/input/evdev.c:240 [inline]
   evdev_pass_values+0x627/0xbd0 drivers/input/evdev.c:278
   evdev_events+0x1e6/0x340 drivers/input/evdev.c:306
   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

-> (&f_owner->lock){....}-{3:3} {
   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
                   generic_add_lease fs/locks.c:1924 [inline]
                   generic_setlease+0xacf/0xfd0 fs/locks.c:2000
                   do_fcntl_add_lease+0x35e/0x470 fs/locks.c:2102
                   fcntl_setlease+0x123/0x180 fs/locks.c:2127
                   do_fcntl+0x8b3/0x1a20 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+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_sigurg+0x55/0x420 fs/fcntl.c:962
                        sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3672
                        queue_oob+0x42c/0x4f0 net/unix/af_unix.c:2368
                        unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2502
                        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
 }
 ... key      at: [<ffffffff9a4bf880>] 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+0x184/0x280 include/net/sock.h:2585
   unix_release_sock+0x74f/0xc80 net/unix/af_unix.c:712
   unix_release+0x92/0xd0 net/unix/af_unix.c:1184
   __sock_release net/socket.c:722 [inline]
   sock_close+0xc3/0x240 net/socket.c:1514
   __fput+0x44f/0xa60 fs/file_table.c:510
   task_work_run+0x1d9/0x270 kernel/task_work.c:233
   get_signal+0x11eb/0x1330 kernel/signal.c:2809
   arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
   __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
   exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
   __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
   syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
   syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
   do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


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:1678
                    do_wait+0x1e7/0x510 kernel/exit.c:1722
                    kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                    call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                    call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                    process_one_work kernel/workqueue.c:3302 [inline]
                    process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                    worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                    kthread+0x388/0x470 kernel/kthread.c:436
                    ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   SOFTIRQ-ON-R at:
                    lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                    __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
                    _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
                    __do_wait+0xde/0x740 kernel/exit.c:1678
                    do_wait+0x1e7/0x510 kernel/exit.c:1722
                    kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                    call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                    call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                    process_one_work kernel/workqueue.c:3302 [inline]
                    process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                    worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                    kthread+0x388/0x470 kernel/kthread.c:436
                    ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   INITIAL USE at:
                   lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:213 [inline]
                   _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:330
                   copy_process+0x2b4c/0x4440 kernel/fork.c:2411
                   kernel_clone+0x284/0x8f0 kernel/fork.c:2721
                   user_mode_thread+0x110/0x180 kernel/fork.c:2797
                   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:1678
                        do_wait+0x1e7/0x510 kernel/exit.c:1722
                        kernel_wait+0xd6/0x1c0 kernel/exit.c:1898
                        call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
                        call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
                        process_one_work kernel/workqueue.c:3302 [inline]
                        process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
                        worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
                        kthread+0x388/0x470 kernel/kthread.c:436
                        ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 }
 ... key      at: [<ffffffff8e60a058>] tasklist_lock+0x18/0x40
 ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
   _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
   send_sigurg+0x12b/0x420 fs/fcntl.c:978
   sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3672
   queue_oob+0x42c/0x4f0 net/unix/af_unix.c:2368
   unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2502
   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


stack backtrace:
CPU: 0 UID: 0 PID: 22366 Comm: syz.4.4396 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_bad_irq_dependency kernel/locking/lockdep.c:2616 [inline]
 check_irq_usage kernel/locking/lockdep.c:2857 [inline]
 check_prev_add kernel/locking/lockdep.c:3169 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x2a94/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_read_lock 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:2368
 unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2502
 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
RIP: 0033:0x7fdb8299ce59
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:00007fdb83942028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fdb82c15fa0 RCX: 00007fdb8299ce59
RDX: 00000000240408c1 RSI: 0000200000000080 RDI: 0000000000000006
RBP: 00007fdb82a32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb82c16038 R14: 00007fdb82c15fa0 R15: 00007fdb82d3fa48
 </TASK>