===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected syzkaller #0 Tainted: G L ----------------------------------------------------- syz.0.2268/13004 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8e20c058 (tasklist_lock){.+.+}-{3:3}, at: send_sigio+0x101/0x370 fs/fcntl.c:932 and this task is already holding: ffff8880340a2ea0 (&f_owner->lock){....}-{3:3}, at: send_sigio+0x38/0x370 fs/fcntl.c:918 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+0x106/0x330 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_event+0x76/0xe0 drivers/input/input.c:395 input_report_key include/linux/input.h:439 [inline] xpad360_process_packet+0xda/0xdd0 drivers/input/joystick/xpad.c:901 xpad_irq_in+0x14e/0x25e0 drivers/input/joystick/xpad.c:1254 __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661 dummy_timer+0xbbd/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x527/0xc30 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1858 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 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] get_partial_node+0x3bc/0x420 mm/slub.c:3550 get_any_partial mm/slub.c:3600 [inline] get_partial mm/slub.c:3634 [inline] ___slab_alloc+0xea3/0x1760 mm/slub.c:4631 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x46c/0x7e0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75 usb_internal_control_msg drivers/usb/core/message.c:96 [inline] usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:154 usb_control_msg_recv+0xd2/0x170 drivers/usb/core/message.c:280 xpad_start_input+0x242/0x310 drivers/input/joystick/xpad.c:1817 input_open_device+0x1f8/0x3b0 drivers/input/input.c:601 evdev_open_device drivers/input/evdev.c:391 [inline] evdev_open+0x4b1/0x5b0 drivers/input/evdev.c:478 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:414 do_dentry_open+0x7ce/0x1420 fs/open.c:962 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x3486/0x3e20 fs/namei.c:4796 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_compat_sys_openat fs/open.c:1498 [inline] __se_compat_sys_openat fs/open.c:1496 [inline] __ia32_compat_sys_openat+0x131/0x160 fs/open.c:1496 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] do_int80_emulation+0x111/0x400 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 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:150 [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:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 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 *** 6 locks held by syz.0.2268/13004: #0: ffff8880223ca420 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffffffff8e6f6010 (file_rwsem){.+.+}-{0:0}, at: __break_lease+0x41c/0x1b80 fs/locks.c:1618 #2: ffff888078292598 (&ctx->flc_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffff888078292598 (&ctx->flc_lock){+.+.}-{3:3}, at: __break_lease+0x429/0x1b80 fs/locks.c:1619 #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: kill_fasync+0x53/0x4d0 fs/fcntl.c:1158 #4: ffff88807a9dd168 (&new->fa_lock){....}-{3:3}, at: kill_fasync_rcu fs/fcntl.c:1135 [inline] #4: ffff88807a9dd168 (&new->fa_lock){....}-{3:3}, at: kill_fasync+0x199/0x4d0 fs/fcntl.c:1159 #5: ffff8880340a2ea0 (&f_owner->lock){....}-{3:3}, at: send_sigio+0x38/0x370 fs/fcntl.c:918 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&dev->event_lock#2){..-.}-{3:3} { IN-SOFTIRQ-W at: lock_acquire+0x106/0x330 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_event+0x76/0xe0 drivers/input/input.c:395 input_report_key include/linux/input.h:439 [inline] xpad360_process_packet+0xda/0xdd0 drivers/input/joystick/xpad.c:901 xpad_irq_in+0x14e/0x25e0 drivers/input/joystick/xpad.c:1254 __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661 dummy_timer+0xbbd/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x527/0xc30 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1858 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 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] get_partial_node+0x3bc/0x420 mm/slub.c:3550 get_any_partial mm/slub.c:3600 [inline] get_partial mm/slub.c:3634 [inline] ___slab_alloc+0xea3/0x1760 mm/slub.c:4631 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x46c/0x7e0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75 usb_internal_control_msg drivers/usb/core/message.c:96 [inline] usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:154 usb_control_msg_recv+0xd2/0x170 drivers/usb/core/message.c:280 xpad_start_input+0x242/0x310 drivers/input/joystick/xpad.c:1817 input_open_device+0x1f8/0x3b0 drivers/input/input.c:601 evdev_open_device drivers/input/evdev.c:391 [inline] evdev_open+0x4b1/0x5b0 drivers/input/evdev.c:478 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:414 do_dentry_open+0x7ce/0x1420 fs/open.c:962 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x3486/0x3e20 fs/namei.c:4796 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_compat_sys_openat fs/open.c:1498 [inline] __se_compat_sys_openat fs/open.c:1496 [inline] __ia32_compat_sys_openat+0x131/0x160 fs/open.c:1496 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] do_int80_emulation+0x111/0x400 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 INITIAL USE at: lock_acquire+0x106/0x330 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+0x535/0x960 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+0x787/0x9c0 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+0xd00/0x1160 drivers/input/input.c:2378 atkbd_connect+0x731/0xa50 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+0x267/0xaf0 drivers/base/dd.c:661 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833 __driver_attach+0x349/0x640 drivers/base/dd.c:1227 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 serio_attach_driver drivers/input/serio/serio.c:777 [inline] serio_handle_event+0x232/0x10d0 drivers/input/serio/serio.c:214 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 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.7+0x0/0x20 -> (&client->buffer_lock){....}-{3:3} { INITIAL USE at: lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __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+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:684 ksys_write+0x150/0x270 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e } ... key at: [] evdev_open.__key.27+0x0/0x20 ... acquired at: __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+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:684 ksys_write+0x150/0x270 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> (&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:195 [inline] _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326 fasync_remove_entry+0xf1/0x1c0 fs/fcntl.c:1012 pipe_fasync+0xa9/0x1e0 fs/pipe.c:756 __fput+0x8a5/0xa70 fs/file_table.c:465 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:44 [inline] exit_to_user_mode_loop+0xed/0x480 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+0x38e/0x540 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL READ USE at: lock_acquire+0x106/0x330 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 wakeup_pipe_readers fs/splice.c:183 [inline] vmsplice_to_pipe fs/splice.c:1558 [inline] __do_sys_vmsplice fs/splice.c:1610 [inline] __se_sys_vmsplice+0x100d/0x1490 fs/splice.c:1580 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 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 __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:684 ksys_write+0x150/0x270 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> (&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:195 [inline] _raw_write_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:326 __f_setown+0x67/0x370 fs/fcntl.c:136 f_setown_ex fs/fcntl.c:254 [inline] do_fcntl+0x171c/0x1a20 fs/fcntl.c:520 do_compat_fcntl64+0x51e/0x7e0 fs/fcntl.c:800 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e INITIAL READ USE at: lock_acquire+0x106/0x330 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 dnotify_handle_event+0x169/0x440 fs/notify/dnotify/dnotify.c:113 fsnotify_handle_event fs/notify/fsnotify.c:357 [inline] send_to_group fs/notify/fsnotify.c:431 [inline] fsnotify+0x168e/0x1ae0 fs/notify/fsnotify.c:648 __fsnotify_parent+0x50d/0x620 fs/notify/fsnotify.c:294 fsnotify_parent include/linux/fsnotify.h:96 [inline] fsnotify_path include/linux/fsnotify.h:113 [inline] fsnotify_file include/linux/fsnotify.h:127 [inline] fsnotify_access include/linux/fsnotify.h:425 [inline] vfs_readv+0x6b5/0x840 fs/read_write.c:1023 do_preadv fs/read_write.c:1132 [inline] __do_compat_sys_preadv fs/read_write.c:1235 [inline] __se_compat_sys_preadv fs/read_write.c:1229 [inline] __ia32_compat_sys_preadv+0x1c6/0x2c0 fs/read_write.c:1229 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 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 __receive_buf drivers/tty/n_tty.c:1632 [inline] n_tty_receive_buf_common+0x974/0x1300 drivers/tty/n_tty.c:1715 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x24a/0x6e0 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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:150 [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:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 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+0x106/0x330 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+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:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 INITIAL USE at: lock_acquire+0x106/0x330 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+0x2199/0x3980 kernel/fork.c:2367 kernel_clone+0x248/0x870 kernel/fork.c:2651 user_mode_thread+0x110/0x180 kernel/fork.c:2727 rest_init+0x23/0x300 init/main.c:722 start_kernel+0x380/0x3d0 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+0x106/0x330 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+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:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 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_sigio+0x101/0x370 fs/fcntl.c:932 kill_fasync_rcu fs/fcntl.c:1144 [inline] kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159 lease_break_callback+0x26/0x30 fs/locks.c:567 __break_lease+0x741/0x1b80 fs/locks.c:1647 vfs_truncate+0x449/0x540 fs/open.c:112 do_sys_truncate+0xf1/0x1c0 fs/open.c:141 __do_compat_sys_truncate fs/open.c:159 [inline] __se_compat_sys_truncate fs/open.c:157 [inline] __ia32_compat_sys_truncate+0x5b/0x70 fs/open.c:157 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e stack backtrace: CPU: 0 UID: 0 PID: 13004 Comm: syz.0.2268 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: 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:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 send_sigio+0x101/0x370 fs/fcntl.c:932 kill_fasync_rcu fs/fcntl.c:1144 [inline] kill_fasync+0x24d/0x4d0 fs/fcntl.c:1159 lease_break_callback+0x26/0x30 fs/locks.c:567 __break_lease+0x741/0x1b80 fs/locks.c:1647 vfs_truncate+0x449/0x540 fs/open.c:112 do_sys_truncate+0xf1/0x1c0 fs/open.c:141 __do_compat_sys_truncate fs/open.c:159 [inline] __se_compat_sys_truncate fs/open.c:157 [inline] __ia32_compat_sys_truncate+0x5b/0x70 fs/open.c:157 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f75539 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:00000000f543650c EFLAGS: 00000206 ORIG_RAX: 000000000000005c RAX: ffffffffffffffda RBX: 0000000080000140 RCX: 0000000000000009 RDX: 0000000000000000 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