INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.9.0-rc8-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:24096 pid: 1 ppid: 0 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x88f/0x1f80 kernel/sched/core.c:4527 schedule+0xcd/0x2b0 kernel/sched/core.c:4602 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:702 device_shutdown+0x18/0x5b5 drivers/base/core.c:3994 kernel_restart_prepare kernel/reboot.c:76 [inline] kernel_restart kernel/reboot.c:246 [inline] __do_sys_reboot.cold+0x5d/0x9d kernel/reboot.c:347 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f1896cbd8c6 Code: Bad RIP value. RSP: 002b:00007ffce4c034b8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1896cbd8c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffce4c03548 R08: 0000000000005001 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000555dd8784150 R15: 00007ffce4c03838 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff872ea808 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a4/0x3e0 kernel/reboot.c:344 1 lock held by khungtaskd/23: #0: ffffffff87313c20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5852 6 locks held by kworker/1:8/12354: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.9.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x74/0xb6 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1da/0x1f4 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+0xd6a/0xfd0 kernel/hung_task.c:295 kthread+0x392/0x470 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: 12354 Comm: kworker/1:8 Not tainted 5.9.0-rc8-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+0x60/0x80 drivers/tty/serial/8250/8250_port.c:448 Code: 0f b6 8d f1 00 00 00 48 8d 7d 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 13 03 5d 40 89 da ec <5b> 0f b6 c0 5d c3 e8 35 fd 3f ff eb c9 e8 5e fd 3f ff eb e6 66 90 RSP: 0018:ffff8881a8776950 EFLAGS: 00000002 RAX: dffffc0000000060 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff822a10fc RDI: ffffffff8a2c0ee0 RBP: ffffffff8a2c0ea0 R08: 0000000000000001 R09: 0000000000000003 R10: 000000000000000a R11: 0000000000000001 R12: 0000000000000020 R13: fffffbfff1458227 R14: fffffbfff14581de R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffce4c02b68 CR3: 00000001d0eaf000 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:3241 uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1942 serial8250_console_write+0x90c/0xa90 drivers/tty/serial/8250/8250_port.c:3313 call_console_drivers kernel/printk/printk.c:1824 [inline] console_unlock+0x881/0xcd0 kernel/printk/printk.c:2501 vprintk_emit+0x21f/0x520 kernel/printk/printk.c:2029 dev_vprintk_emit+0x3eb/0x436 drivers/base/core.c:4129 dev_printk_emit+0xba/0xf1 drivers/base/core.c:4140 __netdev_printk+0x1c6/0x27a net/core/dev.c:10749 netdev_warn+0xd7/0x109 net/core/dev.c:10802 asix_read_cmd.cold+0x3a/0x46 drivers/net/usb/asix_common.c:29 asix_mdio_read+0x1e2/0x320 drivers/net/usb/asix_common.c:466 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+0xb47/0x2720 drivers/net/usb/usbnet.c:1738 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 really_probe+0x291/0xde0 drivers/base/dd.c:553 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_set_configuration+0x1111/0x1880 drivers/usb/core/message.c:2165 usb_generic_driver_probe+0xba/0xf2 drivers/usb/core/generic.c:240 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xde0 drivers/base/dd.c:553 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_new_device.cold+0x71d/0xfd4 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5222 [inline] hub_port_connect_change drivers/usb/core/hub.c:5362 [inline] port_event drivers/usb/core/hub.c:5508 [inline] hub_event+0x2348/0x42b0 drivers/usb/core/hub.c:5590 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294