usb 4-1: New USB device found, idVendor=b1fc, idProduct=70ba, bcdDevice=a0.48 usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=5 usb 4-1: config 0 descriptor?? usb 4-1: USB disconnect, device number 79 INFO: task kworker/0:4:5744 blocked for more than 143 seconds. Not tainted 5.1.0-rc4-319354-g9a33b36 #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:4 D23536 5744 2 0x80000000 Workqueue: usb_hub_wq hub_event Call Trace: schedule+0x8f/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x11/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x800/0x12b0 kernel/locking/mutex.c:1072 i2c_add_adapter+0x1e/0x110 drivers/i2c/i2c-core-base.c:1356 vprbrd_i2c_probe+0x314/0x430 drivers/i2c/busses/i2c-viperboard.c:408 platform_drv_probe+0x95/0x150 drivers/base/platform.c:614 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 platform_device_add+0x35e/0x800 drivers/base/platform.c:451 mfd_add_device+0xc29/0x1130 drivers/mfd/mfd-core.c:249 mfd_add_devices+0x11e/0x1a0 drivers/mfd/mfd-core.c:288 mfd_add_hotplug_devices include/linux/mfd/core.h:128 [inline] vprbrd_probe.cold+0x107/0x184 drivers/mfd/viperboard.c:94 usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021 generic_probe+0xa2/0xda drivers/usb/core/generic.c:210 usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 usb 4-1: new high-speed USB device number 80 using dummy_hcd bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_new_device.cold+0x537/0xccf drivers/usb/core/hub.c:2534 hub_port_connect drivers/usb/core/hub.c:5089 [inline] hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] port_event drivers/usb/core/hub.c:5350 [inline] hub_event+0x138e/0x3b00 drivers/usb/core/hub.c:5432 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269 worker_thread+0x9b/0xe20 kernel/workqueue.c:2415 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 9 locks held by kworker/0:1/12: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 00000000588f1bae ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 00000000f5bb8c82 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 00000000f5bb8c82 (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 #3: 000000006905ff83 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #3: 000000006905ff83 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #4: 0000000040f4bd65 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #4: 0000000040f4bd65 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #5: 00000000623b1aea (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #5: 00000000623b1aea (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #6: 000000005668098f (core_lock){+.+.}, at: i2c_register_adapter+0x507/0xb30 drivers/i2c/i2c-core-base.c:1292 #7: 0000000018573c52 (i2c_register_adapter){+.+.}, at: i2c_lock_bus include/linux/i2c.h:739 [inline] #7: 0000000018573c52 (i2c_register_adapter){+.+.}, at: i2c_smbus_xfer+0x79/0x130 drivers/i2c/i2c-core-smbus.c:533 #8: 00000000d32970f4 (&vb->lock){+.+.}, at: vprbrd_i2c_xfer+0x1a3/0x1b9e drivers/i2c/busses/i2c-viperboard.c:291 5 locks held by kworker/1:0/17: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 00000000938c5e7f ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 0000000007bf0d83 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 0000000007bf0d83 (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 #3: 00000000a42f6b82 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:2994 [inline] #3: 00000000a42f6b82 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5020 [inline] #3: 00000000a42f6b82 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] #3: 00000000a42f6b82 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5350 [inline] #3: 00000000a42f6b82 (&port_dev->status_lock){+.+.}, at: hub_event+0x11a3/0x3b00 drivers/usb/core/hub.c:5432 #4: 0000000069f678f8 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1bb/0x2d30 drivers/usb/core/hub.c:4529 3 locks held by kworker/1:1/22: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 00000000475ea4ab ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 0000000034e04522 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 0000000034e04522 (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 1 lock held by khungtaskd/23: #0: 000000005418696b (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:5059 1 lock held by rsyslogd/5550: #0: 000000002177e1b2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe8/0x100 fs/file.c:801 2 locks held by getty/5641: #0: 000000009ac29ccf (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000c4ae6374 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5642: #0: 00000000d96cc372 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000008801a48c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5643: #0: 0000000041c2ceff (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000002652d78a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5644: #0: 000000005a573304 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000ceef72e1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5645: #0: 00000000ff1bf7a0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000ae9594b9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5646: #0: 000000004c6680a3 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000008bb9ba14 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 2 locks held by getty/5647: #0: 00000000c4fe7318 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x27/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000004c2b45e7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21c/0x1a60 drivers/tty/n_tty.c:2156 6 locks held by kworker/0:3/5738: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 0000000092ff2713 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 0000000006a26b27 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 0000000006a26b27 (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 #3: 00000000568a2a75 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #3: 00000000568a2a75 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #4: 0000000013251c48 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #4: 0000000013251c48 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #5: 000000005668098f (core_lock){+.+.}, at: i2c_add_adapter+0x1e/0x110 drivers/i2c/i2c-core-base.c:1356 7 locks held by kworker/0:4/5744: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 0000000068237cf2 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 000000004c5b3f1f (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 000000004c5b3f1f (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 #3: 000000009a019005 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #3: 000000009a019005 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #4: 000000008dad6548 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #4: 000000008dad6548 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #5: 0000000010172052 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #5: 0000000010172052 (&dev->mutex){....}, at: __device_attach+0x80/0x3a0 drivers/base/dd.c:821 #6: 000000005668098f (core_lock){+.+.}, at: i2c_add_adapter+0x1e/0x110 drivers/i2c/i2c-core-base.c:1356 6 locks held by kworker/1:7/6408: #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000023feb5f5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240 #1: 0000000009ef13ae ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244 #2: 0000000001bb7580 (&dev->mutex){....}, at: device_lock include/linux/device.h:1207 [inline] #2: 0000000001bb7580 (&dev->mutex){....}, at: hub_event+0x18a/0x3b00 drivers/usb/core/hub.c:5378 #3: 00000000b5dd6850 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:2994 [inline] #3: 00000000b5dd6850 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5020 [inline] #3: 00000000b5dd6850 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] #3: 00000000b5dd6850 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5350 [inline] #3: 00000000b5dd6850 (&port_dev->status_lock){+.+.}, at: hub_event+0x11a3/0x3b00 drivers/usb/core/hub.c:5432 #4: 000000006d81b743 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1bb/0x2d30 drivers/usb/core/hub.c:4529 #5: 00000000b410eb36 (ehci_cf_port_reset_rwsem){.+.+}, at: hub_port_reset+0x18a/0x1770 drivers/usb/core/hub.c:2856 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.1.0-rc4-319354-g9a33b36 #3 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+0xe8/0x16e lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x48/0x87 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1bd lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x98e/0xe20 kernel/hung_task.c:288 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.1.0-rc4-319354-g9a33b36 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:174 Code: 90 90 90 90 90 90 90 90 48 8b 34 24 65 48 8b 04 25 00 ee 01 00 65 8b 15 0c 28 90 7e 81 e2 00 01 1f 00 75 2b 8b 90 b0 12 00 00 <83> fa 02 75 20 48 8b 88 b8 12 00 00 8b 80 b4 12 00 00 48 8b 11 48 RSP: 0018:ffff8880a8487cf8 EFLAGS: 00000246 RAX: ffff8880a8471880 RBX: ffff888092b508d0 RCX: ffffffff8ded0c5d RDX: 0000000000000000 RSI: ffffffff8ded0ae8 RDI: 0000000000000004 RBP: ffff888098590a80 R08: ffff8880a8471880 R09: 0000000000000003 R10: ffffed1015a05c27 R11: ffff8880ad02e13b R12: 0000000000000001 R13: 000000000000025b R14: dffffc0000000000 R15: 0000000000000400 FS: 0000000000000000(0000) GS:ffff8880ad000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000068c000 CR3: 000000007684a000 CR4: 00000000001406f0 Call Trace: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:417 [inline] batadv_nc_worker+0xd8/0x770 net/batman-adv/network-coding.c:730 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269 worker_thread+0x9b/0xe20 kernel/workqueue.c:2415 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352