===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected syzkaller #0 Tainted: G L ----------------------------------------------------- syz.3.5034/24427 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8dc0c058 (tasklist_lock){.+.+}-{3:3}, at: send_sigurg+0x12b/0x420 fs/fcntl.c:978 and this task is already holding: ffff88803365a4a0 (&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: (&dev->event_lock#2){..-.}-{3:3} ... which became SOFTIRQ-irq-safe at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] input_inject_event+0xa5/0x340 drivers/input/input.c:419 led_trigger_event+0x138/0x210 drivers/leds/led-triggers.c:420 kbd_propagate_led_state drivers/tty/vt/keyboard.c:1065 [inline] kbd_bh+0x1f3/0x300 drivers/tty/vt/keyboard.c:1244 tasklet_action_common+0x2da/0x4b0 kernel/softirq.c:925 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:704 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 evdev_write+0x2fc/0x480 drivers/input/evdev.c:528 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e to a SOFTIRQ-irq-unsafe lock: (tasklist_lock){.+.+}-{3:3} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x107/0x340 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 kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 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: &dev->event_lock#2 --> &f_owner->lock --> tasklist_lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(tasklist_lock); local_irq_disable(); lock(&dev->event_lock#2); lock(&f_owner->lock); lock(&dev->event_lock#2); *** DEADLOCK *** 2 locks held by syz.3.5034/24427: #0: ffff888078cac420 (&u->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #0: ffff888078cac420 (&u->lock){+.+.}-{3:3}, at: queue_oob+0x1b0/0x4f0 net/unix/af_unix.c:2336 #1: ffff88803365a4a0 (&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: -> (&dev->event_lock#2){..-.}-{3:3} { IN-SOFTIRQ-W at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] input_inject_event+0xa5/0x340 drivers/input/input.c:419 led_trigger_event+0x138/0x210 drivers/leds/led-triggers.c:420 kbd_propagate_led_state drivers/tty/vt/keyboard.c:1065 [inline] kbd_bh+0x1f3/0x300 drivers/tty/vt/keyboard.c:1244 tasklet_action_common+0x2da/0x4b0 kernel/softirq.c:925 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:704 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 evdev_write+0x2fc/0x480 drivers/input/evdev.c:528 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] input_inject_event+0xa5/0x340 drivers/input/input.c:419 kbd_led_trigger_activate+0xbc/0x100 drivers/tty/vt/keyboard.c:1021 led_trigger_set+0x52d/0x950 drivers/leds/led-triggers.c:220 led_match_default_trigger drivers/leds/led-triggers.c:277 [inline] led_trigger_set_default+0x260/0x2a0 drivers/leds/led-triggers.c:300 led_classdev_register_ext+0x73d/0x960 drivers/leds/led-class.c:578 led_classdev_register include/linux/leds.h:274 [inline] input_leds_connect+0x517/0x790 drivers/input/input-leds.c:145 input_attach_handler drivers/input/input.c:994 [inline] input_register_device+0xd00/0x1170 drivers/input/input.c:2378 atkbd_connect+0x73b/0xa50 drivers/input/keyboard/atkbd.c:1340 serio_connect_driver drivers/input/serio/serio.c:44 [inline] serio_driver_probe+0x82/0xd0 drivers/input/serio/serio.c:748 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26d/0xad0 drivers/base/dd.c:659 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:801 driver_probe_device+0x4f/0x240 drivers/base/dd.c:831 __driver_attach+0x349/0x650 drivers/base/dd.c:1225 bus_for_each_dev+0x233/0x2b0 drivers/base/bus.c:383 serio_attach_driver drivers/input/serio/serio.c:777 [inline] serio_handle_event+0x1f9/0x8d0 drivers/input/serio/serio.c:214 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 } ... key at: [] input_allocate_device.__key.6+0x0/0x20 -> (&new->fa_lock){...-}-{3:3} { IN-SOFTIRQ-R at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [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 sock_wake_async+0x137/0x160 net/socket.c:-1 sk_wake_async_rcu include/net/sock.h:2570 [inline] sock_def_readable+0x3c1/0x530 net/core/sock.c:3613 tcp_rcv_established+0x18e3/0x2580 net/ipv4/tcp_input.c:6439 tcp_v6_do_rcv+0x8eb/0x1ba0 net/ipv6/tcp_ipv6.c:1607 tcp_v6_rcv+0x2247/0x2ae0 net/ipv6/tcp_ipv6.c:1877 ip6_protocol_deliver_rcu+0xcb0/0x15c0 net/ipv6/ip6_input.c:438 ip6_input_finish+0x191/0x370 net/ipv6/ip6_input.c:489 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6139 [inline] __netif_receive_skb+0xd3/0x380 net/core/dev.c:6252 process_backlog+0x54f/0x1340 net/core/dev.c:6604 __napi_poll+0xae/0x320 net/core/dev.c:7668 napi_poll net/core/dev.c:7731 [inline] net_rx_action+0x64a/0xe00 net/core/dev.c:7883 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 tcp_sendmsg+0x39/0x50 net/ipv4/tcp.c:1413 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xe5/0x270 net/socket.c:742 sock_write_iter+0x279/0x360 net/socket.c:1195 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326 fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012 sock_fasync+0x85/0xf0 net/socket.c:1480 __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+0xef/0x4e0 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_fast_syscall_32+0x398/0x570 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL READ USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [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 sock_wake_async+0x137/0x160 net/socket.c:-1 sk_wake_async_rcu include/net/sock.h:2570 [inline] sock_def_error_report+0x332/0x390 net/core/sock.c:3598 sk_error_report+0x48/0x270 net/core/sock.c:348 unix_dgram_disconnected net/unix/af_unix.c:630 [inline] unix_dgram_connect+0x96b/0xc20 net/unix/af_unix.c:1580 __sys_connect_file net/socket.c:2089 [inline] __sys_connect+0x316/0x440 net/socket.c:2108 __do_sys_connect net/socket.c:2114 [inline] __se_sys_connect net/socket.c:2111 [inline] __ia32_sys_connect+0x7a/0x90 net/socket.c:2111 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e } ... key at: [] fasync_insert_entry.__key+0x0/0x20 ... acquired at: __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [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 mousedev_notify_readers+0x6f1/0xc00 drivers/input/mousedev.c:309 mousedev_event+0x602/0x1320 drivers/input/mousedev.c:394 input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541 input_pass_values+0x288/0x890 drivers/input/input.c:128 input_event_dispose+0x330/0x6b0 drivers/input/input.c:342 input_inject_event+0x1dd/0x340 drivers/input/input.c:424 evdev_write+0x2fc/0x480 drivers/input/evdev.c:528 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> (&f_owner->lock){....}-{3:3} { INITIAL USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [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:1895 [inline] generic_setlease+0xe1e/0x1280 fs/locks.c:1971 do_fcntl_add_lease+0x34d/0x460 fs/locks.c:2074 fcntl_setdeleg+0x14c/0x1e0 fs/locks.c:2120 do_fcntl+0xd9f/0x1a50 fs/fcntl.c:564 do_compat_fcntl64+0x477/0x720 fs/fcntl.c:800 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL READ USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [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 lease_break_callback+0x26/0x30 fs/locks.c:558 __break_lease+0x730/0x1620 fs/locks.c:1598 break_deleg include/linux/filelock.h:496 [inline] try_break_deleg+0xb1/0x120 include/linux/filelock.h:515 notify_change+0xb5a/0xf40 fs/attr.c:540 chmod_common+0x248/0x400 fs/open.c:647 vfs_fchmod fs/open.c:664 [inline] __do_sys_fchmod fs/open.c:674 [inline] __se_sys_fchmod fs/open.c:667 [inline] __ia32_sys_fchmod+0xf6/0x160 fs/open.c:667 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e } ... key at: [] 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+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 lease_break_callback+0x26/0x30 fs/locks.c:558 __break_lease+0x730/0x1620 fs/locks.c:1598 break_deleg include/linux/filelock.h:496 [inline] try_break_deleg+0xb1/0x120 include/linux/filelock.h:515 notify_change+0xb5a/0xf40 fs/attr.c:540 chmod_common+0x248/0x400 fs/open.c:647 vfs_fchmod fs/open.c:664 [inline] __do_sys_fchmod fs/open.c:674 [inline] __se_sys_fchmod fs/open.c:667 [inline] __ia32_sys_fchmod+0xf6/0x160 fs/open.c:667 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (tasklist_lock){.+.+}-{3:3} { HARDIRQ-ON-R at: lock_acquire+0x107/0x340 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 kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 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+0x107/0x340 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 kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 INITIAL USE at: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x3d/0x50 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+0x381/0x3d0 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+0x107/0x340 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 kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 } ... key at: [] 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 net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x820 net/socket.c:2592 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646 __sys_sendmsg+0x164/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e stack backtrace: CPU: 0 UID: 0 PID: 24427 Comm: syz.3.5034 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: 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+0x2a95/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 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 net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x820 net/socket.c:2592 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646 __sys_sendmsg+0x164/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf700d539 Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f53fd55c EFLAGS: 00000206 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000080002740 RDX: 0000000024004011 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 4: 10 07 adc %al,(%rdi) 6: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi a: 10 08 adc %cl,(%rax) c: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop