INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.11.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:22896 pid: 1 ppid: 0 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4324 [inline] __schedule+0x91b/0x1f90 kernel/sched/core.c:5075 schedule+0xcb/0x270 kernel/sched/core.c:5154 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:704 device_shutdown+0x18/0x5c0 drivers/base/core.c:4186 kernel_restart_prepare kernel/reboot.c:76 [inline] kernel_restart+0x61/0xa0 kernel/reboot.c:246 __do_sys_reboot+0x31e/0x3e0 kernel/reboot.c:349 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3e384738c6 RSP: 002b:00007ffc575fad78 EFLAGS: 00000206 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3e384738c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffc575fae08 R08: 0000000000002800 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 000055dfff35d150 R15: 00007ffc575fb0f8 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff87952c48 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a3/0x3e0 kernel/reboot.c:346 1 lock held by khungtaskd/1271: #0: ffffffff87a78320 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6327 9 locks held by kworker/1:5/7782: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1271 Comm: khungtaskd Not tainted 5.11.0-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+0xfa/0x151 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: 7782 Comm: kworker/1:5 Not tainted 5.11.0-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_in+0x82/0xa0 drivers/tty/serial/8250/8250_port.c:448 Code: d4 c7 04 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 15 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 e8 41 50 31 ff eb a7 e8 6a 50 31 ff eb e4 RSP: 0018:ffffc9000680e898 EFLAGS: 00000002 RAX: dffffc0000000060 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff823ac64c RDI: ffffffff8aee7160 RBP: ffffffff8aee7120 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff823ac63d R11: 000000000000001f R12: 0000000000000000 R13: fffffbfff15dce77 R14: fffffbfff15dce2e R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000203bb38 CR3: 0000000007825000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:113 [inline] wait_for_xmitr+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:2061 serial8250_console_putchar+0x1b/0x50 drivers/tty/serial/8250/8250_port.c:3244 uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1943 serial8250_console_write+0x8fb/0xa90 drivers/tty/serial/8250/8250_port.c:3316 call_console_drivers kernel/printk/printk.c:1862 [inline] console_unlock+0x83b/0xb70 kernel/printk/printk.c:2576 vprintk_emit+0x1f1/0x480 kernel/printk/printk.c:2098 dev_vprintk_emit+0x36e/0x3b2 drivers/base/core.c:4307 dev_printk_emit+0xba/0xf1 drivers/base/core.c:4318 __netdev_printk+0x1c6/0x27a net/core/dev.c:11262 netdev_warn+0xd7/0x109 net/core/dev.c:11315 asix_write_cmd.cold+0x3a/0x46 drivers/net/usb/asix_common.c:52 asix_set_sw_mii drivers/net/usb/asix_common.c:275 [inline] asix_mdio_read+0xef/0x320 drivers/net/usb/asix_common.c:454 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+0xbc4/0x1d90 drivers/base/core.c:3115 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+0xbc4/0x1d90 drivers/base/core.c:3115 usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2555 hub_port_connect drivers/usb/core/hub.c:5223 [inline] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline] port_event drivers/usb/core/hub.c:5509 [inline] hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5591 process_one_work+0x98d/0x1580 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294