INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.12.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:23032 pid: 1 ppid: 0 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4322 [inline] __schedule+0x920/0x1fa0 kernel/sched/core.c:5073 schedule+0xcb/0x270 kernel/sched/core.c:5152 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:704 device_shutdown+0x18/0x5c0 drivers/base/core.c:4313 kernel_restart_prepare kernel/reboot.c:76 [inline] kernel_restart kernel/reboot.c:246 [inline] __do_sys_reboot.cold+0x5d/0x97 kernel/reboot.c:347 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f5e807ac8c6 RSP: 002b:00007ffe6ab3cac8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5e807ac8c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffe6ab3cb58 R08: 0000000000002800 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000561b88dde150 R15: 00007ffe6ab3ce48 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff87952f08 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a4/0x3e0 kernel/reboot.c:344 1 lock held by khungtaskd/1274: #0: ffffffff87a789e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6327 6 locks held by kworker/1:6/10361: #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888103e93938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x871/0x1580 kernel/workqueue.c:2246 #1: ffffc90014087da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1580 kernel/workqueue.c:2250 #2: ffff888108eda220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:740 [inline] #2: ffff888108eda220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4320 drivers/usb/core/hub.c:5590 #3: ffff888107f0a220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:740 [inline] #3: ffff888107f0a220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:889 #4: ffff888113a7f1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:740 [inline] (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:889 #5: ffff888110c6cc60 (&dev->phy_mutex){+.+.}-{3:3}, at: asix_mdio_read+0x9a/0x320 drivers/net/usb/asix_common.c:452 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1274 Comm: khungtaskd Not tainted 5.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x143/0x1db lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x46/0xe0 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1da/0x200 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd32/0xf70 kernel/hung_task.c:294 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10361 Comm: kworker/1:6 Not tainted 5.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_out+0x8a/0xa0 drivers/tty/serial/8250/8250_port.c:454 Code: ff 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 17 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 e8 3a fc 30 ff eb a5 e8 63 fc 30 ff eb e2 90 RSP: 0018:ffffc90014086930 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: ffffffff823cba51 RDI: ffffffff8a6fc1e0 RBP: ffffffff8a6fc1a0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff823cba42 R11: 000000000000001f R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8a6fc1f0 FS: 0000000000000000(0000) GS:ffff8881f6b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe6ab3bff8 CR3: 0000000104201000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_port_out include/linux/serial_core.h:268 [inline] serial8250_console_write+0x8f3/0xae0 drivers/tty/serial/8250/8250_port.c:3302 call_console_drivers kernel/printk/printk.c:1862 [inline] console_unlock+0x897/0xc60 kernel/printk/printk.c:2576 vprintk_emit+0x20a/0x580 kernel/printk/printk.c:2098 dev_vprintk_emit+0x36e/0x3b2 drivers/base/core.c:4434 dev_printk_emit+0xba/0xf1 drivers/base/core.c:4445 __netdev_printk+0x1c6/0x27a net/core/dev.c:11262 netdev_warn+0xd7/0x109 net/core/dev.c:11315 asix_read_cmd.cold+0x3a/0x46 drivers/net/usb/asix_common.c:29 asix_mdio_read+0x149/0x320 drivers/net/usb/asix_common.c:458 asix_phy_reset+0x104/0x170 drivers/net/usb/asix_devices.c:215 ax88172_bind+0x412/0x5d0 drivers/net/usb/asix_devices.c:272 usbnet_probe+0xb25/0x2740 drivers/net/usb/usbnet.c:1702 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 really_probe+0x291/0xe60 drivers/base/dd.c:554 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:914 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbdb/0x1db0 drivers/base/core.c:3242 usb_set_configuration+0x113f/0x1910 drivers/usb/core/message.c:2164 usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xe60 drivers/base/dd.c:554 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:914 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbdb/0x1db0 drivers/base/core.c:3242 usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2556 hub_port_connect drivers/usb/core/hub.c:5276 [inline] hub_port_connect_change drivers/usb/core/hub.c:5416 [inline] port_event drivers/usb/core/hub.c:5562 [inline] hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5644 process_one_work+0x98d/0x1580 kernel/workqueue.c:2275 process_scheduled_works kernel/workqueue.c:2337 [inline] worker_thread+0x82b/0x1120 kernel/workqueue.c:2423 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294