INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.10.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:23432 pid: 1 ppid: 0 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:3779 [inline] __schedule+0x8a2/0x1f30 kernel/sched/core.c:4528 schedule+0xcb/0x270 kernel/sched/core.c:4606 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:702 device_shutdown+0x18/0x5c0 drivers/base/core.c:4007 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/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fdbdd1398c6 RSP: 002b:00007ffca9f10f38 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdbdd1398c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffca9f10fc8 R08: 0000000000002800 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000563cdf652150 R15: 00007ffca9f112b8 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff87128928 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a4/0x3e0 kernel/reboot.c:344 1 lock held by khungtaskd/1268: #0: ffffffff872495a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6254 5 locks held by kworker/1:8/7330: 8 locks held by kworker/0:7/16484: #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888103c76938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x821/0x1520 kernel/workqueue.c:2243 #1: ffffc900110a7da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x854/0x1520 kernel/workqueue.c:2247 #2: ffff888108dd2218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #2: ffff888108dd2218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537 #3: ffff8881372e2218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #3: ffff8881372e2218 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:887 #4: ffff888103b241a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #4: ffff888103b241a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:887 #5: ffff88813b3ecc60 (&dev->phy_mutex){+.+.}-{3:3}, at: asix_mdio_read+0x9a/0x320 drivers/net/usb/asix_common.c:452 #6: ffffffff872495a0 (rcu_read_lock){....}-{1:2}, at: __need_fs_reclaim mm/page_alloc.c:4283 [inline] #6: ffffffff872495a0 (rcu_read_lock){....}-{1:2}, at: fs_reclaim_acquire+0xa1/0xf0 mm/page_alloc.c:4301 #7: ffffffff872495a0 (rcu_read_lock){....}-{1:2}, at: cpu_of kernel/sched/sched.h:1072 [inline] #7: ffffffff872495a0 (rcu_read_lock){....}-{1:2}, at: __update_idle_core+0x39/0x440 kernel/sched/fair.c:6019 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1268 Comm: khungtaskd Not tainted 5.10.0-rc7-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+0x107/0x163 lib/dump_stack.c:118 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:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 16484 Comm: kworker/0:7 Not tainted 5.10.0-rc7-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+0x68/0x80 drivers/tty/serial/8250/8250_port.c:454 Code: 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 15 03 5d 40 44 89 e0 89 da ee <5b> 5d 41 5c c3 e8 7e 36 33 ff eb c7 e8 a7 36 33 ff eb e4 0f 1f 44 RSP: 0018:ffffc900110a6938 EFLAGS: 00000002 RAX: 000000000000005b RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff82372111 RDI: ffffffff8a5cae40 RBP: ffffffff8a5cae00 R08: 0000000000000001 R09: 0000000000000003 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000005b R13: 000000000000005b R14: ffffffff8a5cae00 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f470b0f9000 CR3: 0000000007025000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1942 serial8250_console_write+0x90c/0xa90 drivers/tty/serial/8250/8250_port.c:3316 call_console_drivers kernel/printk/printk.c:1885 [inline] console_unlock+0x848/0xb90 kernel/printk/printk.c:2499 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2028 dev_vprintk_emit+0x2ea/0x32e drivers/base/core.c:4128 dev_printk_emit+0xba/0xf1 drivers/base/core.c:4139 __netdev_printk+0x1c6/0x27a net/core/dev.c:10942 netdev_warn+0xd7/0x109 net/core/dev.c:10995 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+0xb54/0x2740 drivers/net/usb/usbnet.c:1712 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 really_probe+0x291/0xde0 drivers/base/dd.c:554 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+0xbb2/0x1ce0 drivers/base/core.c:2936 usb_set_configuration+0x113c/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+0x291/0xde0 drivers/base/dd.c:554 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+0xbb2/0x1ce0 drivers/base/core.c:2936 usb_new_device.cold+0x71d/0xfe9 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+0x2348/0x42d0 drivers/usb/core/hub.c:5591 process_one_work+0x933/0x1520 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296