INFO: task udevd:5575 blocked for more than 143 seconds. Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24536 pid:5575 tgid:5575 ppid:2839 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x132a/0x3b00 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 device_lock include/linux/device.h:922 [inline] uevent_show+0x187/0x3b0 drivers/base/core.c:2730 dev_attr_show+0x53/0xe0 drivers/base/core.c:2424 sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65 seq_read_iter+0x506/0x12c0 fs/seq_file.c:230 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x8c8/0xc70 fs/read_write.c:570 ksys_read+0x12a/0x240 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f71d512cb6a RSP: 002b:00007ffd881fbcb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00005647afaee650 RCX: 00007f71d512cb6a RDX: 0000000000001000 RSI: 00005647afaf0460 RDI: 0000000000000008 RBP: 00005647afaee650 R08: 0000000000000008 R09: 0000000000000010 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007ffd881fc198 R15: 000000000000000a Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff890c2840 (rcu_read_lock){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] , at: rcu_read_lock include/linux/rcupdate.h:841 [inline] , at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 2 locks held by getty/2897: #0: ffff8881155110a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 4 locks held by udevd/5222: #0: ffff888116efb9e0 (&p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88811bf18488 (&of->mutex#2 ){+.+.}-{4:4} , at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff88811676a788 ( kn->active #5){++++}-{0:0} , at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff888118379198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff888118379198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730 4 locks held by udevd/5262: #0: ffff8881291c90a0 (&p->lock ){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff8881236b0488 (&of->mutex#2){+.+.}-{4:4} , at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff888114f3d788 (kn->active #5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff888118263160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730 5 locks held by kworker/0:5/5281: #0: ffff888106aeb148 ((wq_completion)usb_hub_wq ){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000226fd18 ((work_completion)(&hub->events)){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffff88810b31c198 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:922 [inline] , at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863 #3: ffff888118379198 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:922 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1005 #4: ffff888134e5b160 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:922 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1005 4 locks held by udevd/5575: #0: ffff88811b1a3668 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88810f3b4488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff88810f289b48 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff888131e8a160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff888131e8a160 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730 6 locks held by kworker/1:7/7686: 6 locks held by kworker/0:8/8957: 3 locks held by kworker/1:4/10062: 1 lock held by syz-executor/17731: #0: ffff8881f5838418 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:605 [inline] #0: ffff8881f5838418 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1513 [inline] #0: ffff8881f5838418 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1837 [inline] #0: ffff8881f5838418 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2f0/0x3b00 kernel/sched/core.c:6691 1 lock held by syz.1.3455/18881: 1 lock held by syz.2.3456/18885: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8957 Comm: kworker/0:8 Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:410 Code: ec ad fe 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 cc cc cc cc e8 68 a0 09 ff eb a2 e8 f1 a0 RSP: 0018:ffffc90013566688 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff82ce7bc0 RDI: ffffffff938c2820 RBP: ffffffff938c27e0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000020 R14: fffffbfff2718556 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8882691c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555556ada4a8 CR3: 000000011688a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x137/0x210 drivers/tty/serial/8250/8250_port.c:2098 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3348 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3371 [inline] serial8250_console_write+0xf83/0x1890 drivers/tty/serial/8250/8250_port.c:3456 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x7fe/0xc60 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3325 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450 dev_vprintk_emit drivers/base/core.c:4891 [inline] dev_printk_emit+0xfa/0x140 drivers/base/core.c:4902 __netdev_printk+0x1fb/0x500 net/core/dev.c:12401 netdev_warn+0xe4/0x120 net/core/dev.c:12454 asix_read_cmd+0x10f/0x120 drivers/net/usb/asix_common.c:33 asix_check_host_enable+0xc7/0x240 drivers/net/usb/asix_common.c:102 __asix_mdio_read+0x9c/0x260 drivers/net/usb/asix_common.c:506 asix_phy_reset+0x106/0x1f0 drivers/net/usb/asix_devices.c:215 ax88172_bind+0x41f/0x5d0 drivers/net/usb/asix_devices.c:275 usbnet_probe+0xab8/0x27a0 drivers/net/usb/usbnet.c:1772 usb_probe_interface+0x300/0x9c0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958 bus_for_each_drv+0x156/0x1e0 drivers/base/bus.c:462 __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1030 bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:537 device_add+0x1148/0x1a70 drivers/base/core.c:3666 usb_set_configuration+0x1187/0x1e20 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0xb1/0x110 drivers/usb/core/generic.c:250 usb_probe_device+0xec/0x3e0 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958 bus_for_each_drv+0x156/0x1e0 drivers/base/bus.c:462 __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1030 bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:537 device_add+0x1148/0x1a70 drivers/base/core.c:3666 usb_new_device+0xd07/0x1a20 drivers/usb/core/hub.c:2663 hub_port_connect drivers/usb/core/hub.c:5535 [inline] hub_port_connect_change drivers/usb/core/hub.c:5675 [inline] port_event drivers/usb/core/hub.c:5835 [inline] hub_event+0x2f85/0x5030 drivers/usb/core/hub.c:5917 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245