syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
syzkaller #0 Tainted: G             L     
-----------------------------------------------------
syz.8.9345/4807 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8e40c058 (tasklist_lock){.+.+}-{3:3}, at: send_sigurg+0x12b/0x420 fs/fcntl.c:978

and this task is already holding:
ffff888051c44b20 (&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+0x106/0x330 kernel/locking/lockdep.c:5868
  __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
  _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
  spin_lock include/linux/spinlock.h:341 [inline]
  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 drivers/input/input.c:342 [inline]
  input_handle_event drivers/input/input.c:370 [inline]
  input_repeat_key+0x41a/0x680 drivers/input/input.c:2228
  call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
  expire_timers kernel/time/timer.c:1799 [inline]
  __run_timers kernel/time/timer.c:2373 [inline]
  __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
  run_timer_base kernel/time/timer.c:2394 [inline]
  run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
  handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  invoke_softirq kernel/softirq.c:496 [inline]
  __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
  lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
  rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
  rcu_read_lock include/linux/rcupdate.h:850 [inline]
  page_table_check_clear+0x164/0x5f0 mm/page_table_check.c:77
  ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
  get_and_clear_full_ptes include/linux/pgtable.h:865 [inline]
  zap_present_folio_ptes mm/memory.c:1630 [inline]
  zap_present_ptes mm/memory.c:1712 [inline]
  do_zap_pte_range mm/memory.c:1814 [inline]
  zap_pte_range mm/memory.c:1916 [inline]
  zap_pmd_range mm/memory.c:2008 [inline]
  zap_pud_range mm/memory.c:2036 [inline]
  zap_p4d_range mm/memory.c:2057 [inline]
  unmap_page_range+0x33b3/0x48f0 mm/memory.c:2078
  unmap_single_vma mm/memory.c:2120 [inline]
  unmap_vmas+0x3c0/0x5c0 mm/memory.c:2162
  exit_mmap+0x261/0xd60 mm/mmap.c:1277
  __mmput+0x118/0x430 kernel/fork.c:1174
  exit_mm+0x168/0x220 kernel/exit.c:581
  do_exit+0x62e/0x2310 kernel/exit.c:959
  do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
  __do_sys_exit_group kernel/exit.c:1123 [inline]
  __se_sys_exit_group kernel/exit.c:1121 [inline]
  __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
  x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

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

... which became SOFTIRQ-irq-unsafe at:
...
  lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
  __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
  _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
  __do_wait+0xde/0x740 kernel/exit.c:1672
  do_wait+0x1e7/0x4f0 kernel/exit.c:1716
  kernel_wait+0xd6/0x1c0 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 kernel/workqueue.c:3275 [inline]
  process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
  worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
  kthread+0x388/0x470 kernel/kthread.c:467
  ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &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.8.9345/4807:
 #0: ffff88807d8478a0 (&u->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
 #0: ffff88807d8478a0 (&u->lock){+.+.}-{3:3}, at: queue_oob+0x1b6/0x4f0 net/unix/af_unix.c:2331
 #1: ffff888051c44b20 (&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+0x106/0x330 kernel/locking/lockdep.c:5868
                        __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
                        _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
                        spin_lock include/linux/spinlock.h:341 [inline]
                        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 drivers/input/input.c:342 [inline]
                        input_handle_event drivers/input/input.c:370 [inline]
                        input_repeat_key+0x41a/0x680 drivers/input/input.c:2228
                        call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
                        expire_timers kernel/time/timer.c:1799 [inline]
                        __run_timers kernel/time/timer.c:2373 [inline]
                        __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
                        run_timer_base kernel/time/timer.c:2394 [inline]
                        run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
                        handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
                        __do_softirq kernel/softirq.c:656 [inline]
                        invoke_softirq kernel/softirq.c:496 [inline]
                        __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
                        irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
                        instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
                        sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
                        asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
                        lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
                        rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
                        rcu_read_lock include/linux/rcupdate.h:850 [inline]
                        page_table_check_clear+0x164/0x5f0 mm/page_table_check.c:77
                        ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
                        get_and_clear_full_ptes include/linux/pgtable.h:865 [inline]
                        zap_present_folio_ptes mm/memory.c:1630 [inline]
                        zap_present_ptes mm/memory.c:1712 [inline]
                        do_zap_pte_range mm/memory.c:1814 [inline]
                        zap_pte_range mm/memory.c:1916 [inline]
                        zap_pmd_range mm/memory.c:2008 [inline]
                        zap_pud_range mm/memory.c:2036 [inline]
                        zap_p4d_range mm/memory.c:2057 [inline]
                        unmap_page_range+0x33b3/0x48f0 mm/memory.c:2078
                        unmap_single_vma mm/memory.c:2120 [inline]
                        unmap_vmas+0x3c0/0x5c0 mm/memory.c:2162
                        exit_mmap+0x261/0xd60 mm/mmap.c:1277
                        __mmput+0x118/0x430 kernel/fork.c:1174
                        exit_mm+0x168/0x220 kernel/exit.c:581
                        do_exit+0x62e/0x2310 kernel/exit.c:959
                        do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
                        __do_sys_exit_group kernel/exit.c:1123 [inline]
                        __se_sys_exit_group kernel/exit.c:1121 [inline]
                        __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
                        x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
                        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                        do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                        entry_SYSCALL_64_after_hwframe+0x77/0x7f
     INITIAL USE at:
                       lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                       __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
                       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
                       spin_lock include/linux/spinlock.h:341 [inline]
                       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+0x1dd/0x340 drivers/input/input.c:424
                       evdev_write+0x325/0x4c0 drivers/input/evdev.c:528
                       vfs_write+0x29a/0xb90 fs/read_write.c:686
                       ksys_write+0x150/0x270 fs/read_write.c:740
                       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                       do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                       entry_SYSCALL_64_after_hwframe+0x77/0x7f
   }
   ... key      at: [<ffffffff9a5cb420>] evdev_open.__key.27+0x0/0x20
 -> (&new->fa_lock){....}-{3:3} {
    INITIAL USE at:
                     lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                     __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                     _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                     fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012
                     __fput+0x8a5/0xa70 fs/file_table.c:466
                     task_work_run+0x1d9/0x270 kernel/task_work.c:233
                     resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
                     __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
                     exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
                     __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
                     syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
                     syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
                     do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
                     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    INITIAL READ USE at:
                          lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                          __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
                          _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:236
                          kill_fasync_rcu fs/fcntl.c:1135 [inline]
                          kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
                          __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+0x1dd/0x340 drivers/input/input.c:424
                          evdev_write+0x325/0x4c0 drivers/input/evdev.c:528
                          vfs_write+0x29a/0xb90 fs/read_write.c:686
                          ksys_write+0x150/0x270 fs/read_write.c:740
                          do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                          do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                          entry_SYSCALL_64_after_hwframe+0x77/0x7f
  }
  ... key      at: [<ffffffff9a2ac140>] fasync_insert_entry.__key+0x0/0x20
  ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
   _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:236
   kill_fasync_rcu fs/fcntl.c:1135 [inline]
   kill_fasync+0x199/0x4d0 fs/fcntl.c:1159
   __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+0x1dd/0x340 drivers/input/input.c:424
   evdev_write+0x325/0x4c0 drivers/input/evdev.c:528
   vfs_write+0x29a/0xb90 fs/read_write.c:686
   ksys_write+0x150/0x270 fs/read_write.c:740
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> (&f_owner->lock){....}-{3:3} {
   INITIAL USE at:
                   lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                   _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                   __f_setown+0x67/0x370 fs/fcntl.c:136
                   generic_add_lease fs/locks.c:1908 [inline]
                   generic_setlease+0xacf/0xf90 fs/locks.c:1984
                   do_fcntl_add_lease+0x35e/0x470 fs/locks.c:2086
                   fcntl_setdeleg+0x14c/0x1e0 fs/locks.c:2132
                   do_fcntl+0xe6d/0x1a20 fs/fcntl.c:564
                   __do_sys_fcntl fs/fcntl.c:602 [inline]
                   __se_sys_fcntl+0xc8/0x150 fs/fcntl.c:587
                   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                   do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL READ USE at:
                        lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                        __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
                        _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:236
                        send_sigio+0x38/0x370 fs/fcntl.c:918
                        dnotify_handle_event+0x169/0x440 fs/notify/dnotify/dnotify.c:113
                        fsnotify_handle_event fs/notify/fsnotify.c:301 [inline]
                        send_to_group fs/notify/fsnotify.c:375 [inline]
                        fsnotify+0x168e/0x1ae0 fs/notify/fsnotify.c:592
                        __fsnotify_parent+0x50d/0x620 fs/notify/fsnotify.c:238
                        fsnotify_parent include/linux/fsnotify.h:96 [inline]
                        fsnotify_dentry include/linux/fsnotify.h:108 [inline]
                        fsnotify_xattr include/linux/fsnotify.h:465 [inline]
                        __vfs_setxattr_noperm+0x4cd/0x660 fs/xattr.c:237
                        vfs_setxattr+0x163/0x360 fs/xattr.c:321
                        do_setxattr fs/xattr.c:636 [inline]
                        filename_setxattr+0x296/0x630 fs/xattr.c:664
                        path_setxattrat+0x3eb/0x440 fs/xattr.c:708
                        __do_sys_setxattr fs/xattr.c:742 [inline]
                        __se_sys_setxattr fs/xattr.c:738 [inline]
                        __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:738
                        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                        do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
                        entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff9a2ac120>] file_f_owner_allocate.__key+0x0/0x20
 ... acquired at:
   __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
   _raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:236
   send_sigio+0x38/0x370 fs/fcntl.c:918
   kill_fasync_rcu fs/fcntl.c:1144 [inline]
   kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159
   tiocsti+0x218/0x2a0 drivers/tty/tty_io.c:2290
   tty_ioctl+0x626/0xde0 drivers/tty/tty_io.c:2706
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:597 [inline]
   __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
-> (tasklist_lock){.+.+}-{3:3} {
   HARDIRQ-ON-R at:
                    lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                    __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                    _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                    __do_wait+0xde/0x740 kernel/exit.c:1672
                    do_wait+0x1e7/0x4f0 kernel/exit.c:1716
                    kernel_wait+0xd6/0x1c0 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 kernel/workqueue.c:3275 [inline]
                    process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
                    worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
                    kthread+0x388/0x470 kernel/kthread.c:467
                    ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   SOFTIRQ-ON-R at:
                    lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                    __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                    _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                    __do_wait+0xde/0x740 kernel/exit.c:1672
                    do_wait+0x1e7/0x4f0 kernel/exit.c:1716
                    kernel_wait+0xd6/0x1c0 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 kernel/workqueue.c:3275 [inline]
                    process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
                    worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
                    kthread+0x388/0x470 kernel/kthread.c:467
                    ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   INITIAL USE at:
                   lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:211 [inline]
                   _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326
                   copy_process+0x247a/0x3cf0 kernel/fork.c:2369
                   kernel_clone+0x248/0x870 kernel/fork.c:2654
                   user_mode_thread+0x110/0x180 kernel/fork.c:2730
                   rest_init+0x23/0x300 init/main.c:725
                   start_kernel+0x385/0x3d0 init/main.c:1210
                   x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
                   x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
                   common_startup_64+0x13e/0x147
   INITIAL READ USE at:
                        lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
                        __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
                        _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
                        __do_wait+0xde/0x740 kernel/exit.c:1672
                        do_wait+0x1e7/0x4f0 kernel/exit.c:1716
                        kernel_wait+0xd6/0x1c0 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 kernel/workqueue.c:3275 [inline]
                        process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
                        worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
                        kthread+0x388/0x470 kernel/kthread.c:467
                        ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 }
 ... key      at: [<ffffffff8e40c058>] tasklist_lock+0x18/0x40
 ... acquired at:
   __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
   _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
   send_sigurg+0x12b/0x420 fs/fcntl.c:978
   sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3669
   queue_oob+0x42c/0x4f0 net/unix/af_unix.c:2352
   unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2486
   sock_sendmsg_nosec net/socket.c:727 [inline]
   __sock_sendmsg net/socket.c:742 [inline]
   ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
   ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
   __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2735
   __do_sys_sendmmsg net/socket.c:2762 [inline]
   __se_sys_sendmmsg net/socket.c:2759 [inline]
   __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2759
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f


stack backtrace:
CPU: 1 UID: 0 PID: 4807 Comm: syz.8.9345 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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+0x106/0x330 kernel/locking/lockdep.c:5868
 __raw_read_lock include/linux/rwlock_api_smp.h:161 [inline]
 _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
 send_sigurg+0x12b/0x420 fs/fcntl.c:978
 sk_send_sigurg+0x6c/0x2e0 net/core/sock.c:3669
 queue_oob+0x42c/0x4f0 net/unix/af_unix.c:2352
 unix_stream_sendmsg+0xcb1/0xe80 net/unix/af_unix.c:2486
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2735
 __do_sys_sendmmsg net/socket.c:2762 [inline]
 __se_sys_sendmmsg net/socket.c:2759 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2759
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9743f9bf79
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:00007f9744e1c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f9744215fa0 RCX: 00007f9743f9bf79
RDX: 0000000000000001 RSI: 0000200000006c40 RDI: 0000000000000003
RBP: 00007f97440327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000040015 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9744216038 R14: 00007f9744215fa0 R15: 00007fff7cfecd78
 </TASK>