===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected syzkaller #0 Tainted: G L ----------------------------------------------------- syz.4.2988/19113 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8e00c098 (tasklist_lock){.+.+}-{3:3}, at: send_sigurg+0xed/0xc80 fs/fcntl.c:978 and this task is already holding: ffff888058c590a0 (&f_owner->lock){....}-{3:3}, at: send_sigurg+0x5f/0xc80 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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] evdev_pass_values+0x10e/0x9b0 drivers/input/evdev.c:261 evdev_events+0x1bb/0x390 drivers/input/evdev.c:306 input_pass_values+0x74e/0x880 drivers/input/input.c:128 input_event_dispose drivers/input/input.c:353 [inline] input_handle_event+0xb29/0x14d0 drivers/input/input.c:370 input_event drivers/input/input.c:396 [inline] input_event+0x8e/0xd0 drivers/input/input.c:391 hidinput_hid_event+0x90b/0x2470 drivers/hid/hid-input.c:1747 hid_process_event+0x4b7/0x5e0 drivers/hid/hid-core.c:1565 hid_process_report drivers/hid/hid-core.c:1713 [inline] hid_report_raw_event+0xa33/0x12c0 drivers/hid/hid-core.c:2074 __hid_input_report.constprop.0+0x33f/0x470 drivers/hid/hid-core.c:2144 hid_irq_in+0x35e/0x870 drivers/hid/usbhid/hid-core.c:286 __usb_hcd_giveback_urb+0x38b/0x610 drivers/usb/core/hcd.c:1661 usb_hcd_giveback_urb+0x39b/0x450 drivers/usb/core/hcd.c:1745 dummy_timer+0x1809/0x3ad0 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 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+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5833 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock_sched include/linux/rcupdate.h:958 [inline] pfn_valid include/linux/mmzone.h:2183 [inline] page_table_check_set+0xb8/0xa40 mm/page_table_check.c:105 __page_table_check_ptes_set+0x276/0x4e0 mm/page_table_check.c:212 page_table_check_ptes_set include/linux/page_table_check.h:76 [inline] set_ptes include/linux/pgtable.h:292 [inline] __ptep_modify_prot_commit include/linux/pgtable.h:1356 [inline] ptep_modify_prot_commit include/linux/pgtable.h:1391 [inline] modify_prot_commit_ptes include/linux/pgtable.h:1465 [inline] prot_commit_flush_ptes+0x2aa/0x560 mm/mprotect.c:136 change_pte_range mm/mprotect.c:297 [inline] change_pmd_range mm/mprotect.c:507 [inline] change_pud_range mm/mprotect.c:570 [inline] change_p4d_range mm/mprotect.c:596 [inline] change_protection_range mm/mprotect.c:624 [inline] change_protection+0x1624/0x3870 mm/mprotect.c:658 mprotect_fixup+0x642/0xb80 mm/mprotect.c:774 do_mprotect_pkey+0x9bc/0xd40 mm/mprotect.c:930 __do_sys_mprotect mm/mprotect.c:951 [inline] __se_sys_mprotect mm/mprotect.c:948 [inline] __x64_sys_mprotect+0x78/0xc0 mm/mprotect.c:948 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 __do_wait+0x105/0x890 kernel/exit.c:1672 do_wait+0x21d/0x570 kernel/exit.c:1716 kernel_wait+0x9f/0x160 kernel/exit.c:1892 call_usermodehelper_exec_sync kernel/umh.c:136 [inline] call_usermodehelper_exec_work+0xf1/0x170 kernel/umh.c:163 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: &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); lock(&client->buffer_lock); *** DEADLOCK *** 2 locks held by syz.4.2988/19113: #0: ffff888033736fe0 (&u->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #0: ffff888033736fe0 (&u->lock){+.+.}-{3:3}, at: queue_oob net/unix/af_unix.c:2336 [inline] #0: ffff888033736fe0 (&u->lock){+.+.}-{3:3}, at: unix_stream_sendmsg+0xd33/0x1320 net/unix/af_unix.c:2491 #1: ffff888058c590a0 (&f_owner->lock){....}-{3:3}, at: send_sigurg+0x5f/0xc80 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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] evdev_pass_values+0x10e/0x9b0 drivers/input/evdev.c:261 evdev_events+0x1bb/0x390 drivers/input/evdev.c:306 input_pass_values+0x74e/0x880 drivers/input/input.c:128 input_event_dispose drivers/input/input.c:353 [inline] input_handle_event+0xb29/0x14d0 drivers/input/input.c:370 input_event drivers/input/input.c:396 [inline] input_event+0x8e/0xd0 drivers/input/input.c:391 hidinput_hid_event+0x90b/0x2470 drivers/hid/hid-input.c:1747 hid_process_event+0x4b7/0x5e0 drivers/hid/hid-core.c:1565 hid_process_report drivers/hid/hid-core.c:1713 [inline] hid_report_raw_event+0xa33/0x12c0 drivers/hid/hid-core.c:2074 __hid_input_report.constprop.0+0x33f/0x470 drivers/hid/hid-core.c:2144 hid_irq_in+0x35e/0x870 drivers/hid/usbhid/hid-core.c:286 __usb_hcd_giveback_urb+0x38b/0x610 drivers/usb/core/hcd.c:1661 usb_hcd_giveback_urb+0x39b/0x450 drivers/usb/core/hcd.c:1745 dummy_timer+0x1809/0x3ad0 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 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+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5833 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock_sched include/linux/rcupdate.h:958 [inline] pfn_valid include/linux/mmzone.h:2183 [inline] page_table_check_set+0xb8/0xa40 mm/page_table_check.c:105 __page_table_check_ptes_set+0x276/0x4e0 mm/page_table_check.c:212 page_table_check_ptes_set include/linux/page_table_check.h:76 [inline] set_ptes include/linux/pgtable.h:292 [inline] __ptep_modify_prot_commit include/linux/pgtable.h:1356 [inline] ptep_modify_prot_commit include/linux/pgtable.h:1391 [inline] modify_prot_commit_ptes include/linux/pgtable.h:1465 [inline] prot_commit_flush_ptes+0x2aa/0x560 mm/mprotect.c:136 change_pte_range mm/mprotect.c:297 [inline] change_pmd_range mm/mprotect.c:507 [inline] change_pud_range mm/mprotect.c:570 [inline] change_p4d_range mm/mprotect.c:596 [inline] change_protection_range mm/mprotect.c:624 [inline] change_protection+0x1624/0x3870 mm/mprotect.c:658 mprotect_fixup+0x642/0xb80 mm/mprotect.c:774 do_mprotect_pkey+0x9bc/0xd40 mm/mprotect.c:930 __do_sys_mprotect mm/mprotect.c:951 [inline] __se_sys_mprotect mm/mprotect.c:948 [inline] __x64_sys_mprotect+0x78/0xc0 mm/mprotect.c:948 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] evdev_pass_values+0x10e/0x9b0 drivers/input/evdev.c:261 evdev_events+0x1bb/0x390 drivers/input/evdev.c:306 input_pass_values+0x74e/0x880 drivers/input/input.c:128 input_event_dispose drivers/input/input.c:353 [inline] input_handle_event+0xb29/0x14d0 drivers/input/input.c:370 input_inject_event+0x1e8/0x3b0 drivers/input/input.c:424 kd_sound_helper+0x20f/0x280 drivers/tty/vt/keyboard.c:261 input_handler_for_each_handle+0xd7/0x250 drivers/input/input.c:2520 kd_mksound+0x88/0x130 drivers/tty/vt/keyboard.c:280 handle_ascii drivers/tty/vt/vt.c:2327 [inline] do_con_trol drivers/tty/vt/vt.c:2644 [inline] do_con_write+0x3246/0x8280 drivers/tty/vt/vt.c:3228 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3565 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x434/0x1280 drivers/tty/n_tty.c:2366 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.constprop.0+0x503/0x9b0 drivers/tty/tty_io.c:1081 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d3/0x11d0 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f } ... key at: [] __key.88+0x0/0x40 -> (&new->fa_lock){...-}-{3:3} { IN-SOFTIRQ-R at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:236 kill_fasync_rcu fs/fcntl.c:1135 [inline] kill_fasync fs/fcntl.c:1159 [inline] kill_fasync+0x138/0x510 fs/fcntl.c:1152 sock_wake_async+0x132/0x160 net/socket.c:1509 sk_wake_async_rcu include/net/sock.h:2570 [inline] sk_wake_async_rcu include/net/sock.h:2567 [inline] sock_def_readable+0x4f7/0x5d0 net/core/sock.c:3613 packet_rcv+0xed0/0x17a0 net/packet/af_packet.c:2209 deliver_skb+0x1ae/0x260 net/core/dev.c:2473 __netif_receive_skb_core.constprop.0+0x1730/0x35b0 net/core/dev.c:5972 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6135 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6250 process_backlog+0x4a2/0x1650 net/core/dev.c:6602 __napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x9f9/0xfa0 net/core/dev.c:7881 handle_softirqs+0x219/0x950 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:510 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline] __dev_queue_xmit+0x797/0x4650 net/core/dev.c:4844 dev_queue_xmit include/linux/netdevice.h:3381 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip6_finish_output2+0x1184/0x1cf0 net/ipv6/ip6_output.c:136 __ip6_finish_output+0x3cd/0x1010 net/ipv6/ip6_output.c:209 ip6_finish_output net/ipv6/ip6_output.c:220 [inline] NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x253/0x710 net/ipv6/ip6_output.c:247 dst_output+0xa8/0x4b0 include/net/dst.h:464 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] mld_sendpack+0xa30/0xed0 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x740/0xbf0 net/ipv6/mcast.c:2693 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x36/0x50 kernel/locking/spinlock.c:326 fasync_remove_entry+0xb2/0x1e0 fs/fcntl.c:1012 fasync_helper+0xaf/0xd0 fs/fcntl.c:1115 sock_fasync+0x92/0x140 net/socket.c:1480 __fput+0x96b/0xb70 fs/file_table.c:465 task_work_run+0x150/0x240 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+0xfb/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f INITIAL READ USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:236 kill_fasync_rcu fs/fcntl.c:1135 [inline] kill_fasync fs/fcntl.c:1159 [inline] kill_fasync+0x138/0x510 fs/fcntl.c:1152 sock_wake_async+0x132/0x160 net/socket.c:1509 sk_wake_async_rcu include/net/sock.h:2570 [inline] sk_wake_async_rcu include/net/sock.h:2567 [inline] sock_def_readable+0x4f7/0x5d0 net/core/sock.c:3613 packet_rcv+0xed0/0x17a0 net/packet/af_packet.c:2209 deliver_skb+0x1ae/0x260 net/core/dev.c:2473 __netif_receive_skb_core.constprop.0+0x1730/0x35b0 net/core/dev.c:5972 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6135 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6250 netif_receive_skb_internal net/core/dev.c:6336 [inline] netif_receive_skb+0x137/0x760 net/core/dev.c:6395 tun_rx_batched.isra.0+0x3ee/0x740 drivers/net/tun.c:1509 tun_get_user+0x28b2/0x3cc0 drivers/net/tun.c:1953 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d3/0x11d0 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f } ... key at: [] __key.0+0x0/0x40 ... acquired at: __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0x74/0x90 kernel/locking/spinlock.c:236 kill_fasync_rcu fs/fcntl.c:1135 [inline] kill_fasync fs/fcntl.c:1159 [inline] kill_fasync+0x138/0x510 fs/fcntl.c:1152 __pass_event drivers/input/evdev.c:240 [inline] evdev_pass_values+0x619/0x9b0 drivers/input/evdev.c:278 evdev_events+0x1bb/0x390 drivers/input/evdev.c:306 input_pass_values+0x74e/0x880 drivers/input/input.c:128 input_event_dispose drivers/input/input.c:342 [inline] input_handle_event+0xf00/0x14d0 drivers/input/input.c:370 input_inject_event+0x1e8/0x3b0 drivers/input/input.c:424 evdev_write+0x457/0x750 drivers/input/evdev.c:528 vfs_write+0x2a0/0x11d0 fs/read_write.c:684 ksys_write+0x1f8/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x36/0x50 kernel/locking/spinlock.c:326 __f_setown+0x61/0x3c0 fs/fcntl.c:136 generic_add_lease fs/locks.c:1895 [inline] generic_setlease+0xf0f/0x1330 fs/locks.c:1971 kernel_setlease+0x106/0x140 fs/locks.c:2020 vfs_setlease+0x1e8/0x280 fs/locks.c:2053 do_fcntl_add_lease+0x3c4/0x550 fs/locks.c:2074 fcntl_setlease+0xfc/0x180 fs/locks.c:2099 do_fcntl+0x153b/0x1660 fs/fcntl.c:535 __do_sys_fcntl fs/fcntl.c:602 [inline] __se_sys_fcntl fs/fcntl.c:587 [inline] __x64_sys_fcntl+0x163/0x200 fs/fcntl.c:587 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f INITIAL READ USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0x74/0x90 kernel/locking/spinlock.c:236 send_sigio+0x31/0x3e0 fs/fcntl.c:918 kill_fasync_rcu fs/fcntl.c:1144 [inline] kill_fasync fs/fcntl.c:1159 [inline] kill_fasync+0x214/0x510 fs/fcntl.c:1152 n_hdlc_tty_receive+0x1ca/0x2d0 drivers/tty/n_hdlc.c:408 tiocsti drivers/tty/tty_io.c:2290 [inline] tty_ioctl+0x583/0x1650 drivers/tty/tty_io.c:2706 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f } ... key at: [] __key.1+0x0/0x40 ... acquired at: __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:160 [inline] _raw_read_lock_irqsave+0x74/0x90 kernel/locking/spinlock.c:236 send_sigio+0x31/0x3e0 fs/fcntl.c:918 kill_fasync_rcu fs/fcntl.c:1144 [inline] kill_fasync fs/fcntl.c:1159 [inline] kill_fasync+0x214/0x510 fs/fcntl.c:1152 n_hdlc_tty_receive+0x1ca/0x2d0 drivers/tty/n_hdlc.c:408 tiocsti drivers/tty/tty_io.c:2290 [inline] tty_ioctl+0x583/0x1650 drivers/tty/tty_io.c:2706 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 __do_wait+0x105/0x890 kernel/exit.c:1672 do_wait+0x21d/0x570 kernel/exit.c:1716 kernel_wait+0x9f/0x160 kernel/exit.c:1892 call_usermodehelper_exec_sync kernel/umh.c:136 [inline] call_usermodehelper_exec_work+0xf1/0x170 kernel/umh.c:163 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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 kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 __do_wait+0x105/0x890 kernel/exit.c:1672 do_wait+0x21d/0x570 kernel/exit.c:1716 kernel_wait+0x9f/0x160 kernel/exit.c:1892 call_usermodehelper_exec_sync kernel/umh.c:136 [inline] call_usermodehelper_exec_work+0xf1/0x170 kernel/umh.c:163 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x36/0x50 kernel/locking/spinlock.c:326 copy_process+0x4668/0x7430 kernel/fork.c:2367 kernel_clone+0xfc/0x910 kernel/fork.c:2651 user_mode_thread+0xc8/0x110 kernel/fork.c:2727 rest_init+0x23/0x2b0 init/main.c:722 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 INITIAL READ USE at: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 __do_wait+0x105/0x890 kernel/exit.c:1672 do_wait+0x21d/0x570 kernel/exit.c:1716 kernel_wait+0x9f/0x160 kernel/exit.c:1892 call_usermodehelper_exec_sync kernel/umh.c:136 [inline] call_usermodehelper_exec_work+0xf1/0x170 kernel/umh.c:163 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 send_sigurg+0xed/0xc80 fs/fcntl.c:978 sk_send_sigurg+0x76/0x360 net/core/sock.c:3669 queue_oob net/unix/af_unix.c:2357 [inline] unix_stream_sendmsg+0xfa3/0x1320 net/unix/af_unix.c:2491 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmmsg+0x200/0x420 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2762 [inline] __se_sys_sendmmsg net/socket.c:2759 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f stack backtrace: CPU: 0 UID: 60928 PID: 19113 Comm: syz.4.2988 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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_bad_irq_dependency kernel/locking/lockdep.c:2616 [inline] check_irq_usage+0x8e6/0xbc0 kernel/locking/lockdep.c:2857 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+0x167f/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 send_sigurg+0xed/0xc80 fs/fcntl.c:978 sk_send_sigurg+0x76/0x360 net/core/sock.c:3669 queue_oob net/unix/af_unix.c:2357 [inline] unix_stream_sendmsg+0xfa3/0x1320 net/unix/af_unix.c:2491 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmmsg+0x200/0x420 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2762 [inline] __se_sys_sendmmsg net/socket.c:2759 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f59b558f749 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:00007f59b642a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f59b57e5fa0 RCX: 00007f59b558f749 RDX: 0000000000000001 RSI: 0000200000011500 RDI: 0000000000000003 RBP: 00007f59b5613f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000040015 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f59b57e6038 R14: 00007f59b57e5fa0 R15: 00007ffc8b2b8208