INFO: task kworker/0:3:4102 blocked for more than 143 seconds.
Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:3 state:D stack:22144 pid: 4102 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5183 [inline]
__schedule+0x93f/0x26f0 kernel/sched/core.c:6495
schedule+0xda/0x1b0 kernel/sched/core.c:6571
rwsem_down_write_slowpath+0x59c/0x11e0 kernel/locking/rwsem.c:1182
__down_write_common kernel/locking/rwsem.c:1297 [inline]
__down_write_common kernel/locking/rwsem.c:1294 [inline]
__down_write kernel/locking/rwsem.c:1306 [inline]
down_write+0x135/0x150 kernel/locking/rwsem.c:1553
usb_register_dev drivers/usb/core/file.c:187 [inline]
usb_register_dev+0x198/0x7e0 drivers/usb/core/file.c:156
wdm_create+0x118a/0x17c0 drivers/usb/class/cdc-wdm.c:1112
wdm_probe+0x225/0x2d0 drivers/usb/class/cdc-wdm.c:1164
usb_probe_interface+0x30b/0x7f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:560 [inline]
really_probe+0x249/0xb90 drivers/base/dd.c:639
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808
__device_attach_driver+0x1d0/0x2e0 drivers/base/dd.c:936
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427
__device_attach+0x1e4/0x530 drivers/base/dd.c:1008
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487
device_add+0xbd5/0x1e90 drivers/base/core.c:3517
usb_set_configuration+0x1019/0x1900 drivers/usb/core/message.c:2170
usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238
usb_probe_device+0xd4/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:560 [inline]
really_probe+0x249/0xb90 drivers/base/dd.c:639
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808
__device_attach_driver+0x1d0/0x2e0 drivers/base/dd.c:936
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427
__device_attach+0x1e4/0x530 drivers/base/dd.c:1008
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487
device_add+0xbd5/0x1e90 drivers/base/core.c:3517
usb_new_device.cold+0x685/0x10ad drivers/usb/core/hub.c:2573
hub_port_connect drivers/usb/core/hub.c:5353 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]
hub_event+0x26c7/0x45e0 drivers/usb/core/hub.c:5735
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2ea/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
INFO: task syz-executor.1:10132 blocked for more than 143 seconds.
Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1 state:D stack:29184 pid:10132 ppid: 1303 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5183 [inline]
__schedule+0x93f/0x26f0 kernel/sched/core.c:6495
schedule+0xda/0x1b0 kernel/sched/core.c:6571
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6630
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0xa44/0x1350 kernel/locking/mutex.c:747
sisusb_open+0xb2/0x4d0 drivers/usb/misc/sisusbvga/sisusb.c:2396
usb_open+0x204/0x2e0 drivers/usb/core/file.c:48
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x6c7/0x12a0 fs/open.c:882
do_open fs/namei.c:3557 [inline]
path_openat+0x1c92/0x28f0 fs/namei.c:3691
do_filp_open+0x1b6/0x400 fs/namei.c:3718
do_sys_openat2+0x16d/0x4c0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1337
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f937c00c654
RSP: 002b:00007f937b78cca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f937c17c120 RCX: 00007f937c00c654
RDX: 0000000000000002 RSI: 00007f937b78cd40 RDI: 00000000ffffff9c
RBP: 00007f937b78cd40 R08: 0000000000000000 R09: 000000000000000f
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002
R13: 00007ffc67bbcb2f R14: 00007f937b78d300 R15: 0000000000022000
INFO: task syz-executor.5:10119 blocked for more than 144 seconds.
Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5 state:D stack:29120 pid:10119 ppid: 1305 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5183 [inline]
__schedule+0x93f/0x26f0 kernel/sched/core.c:6495
schedule+0xda/0x1b0 kernel/sched/core.c:6571
rwsem_down_read_slowpath+0x59f/0xb10 kernel/locking/rwsem.c:1087
__down_read_common kernel/locking/rwsem.c:1252 [inline]
__down_read kernel/locking/rwsem.c:1261 [inline]
down_read+0xe2/0x450 kernel/locking/rwsem.c:1501
usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x6c7/0x12a0 fs/open.c:882
do_open fs/namei.c:3557 [inline]
path_openat+0x1c92/0x28f0 fs/namei.c:3691
do_filp_open+0x1b6/0x400 fs/namei.c:3718
do_sys_openat2+0x16d/0x4c0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1337
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0ff9022654
RSP: 002b:00007f0ff87e4ca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0ff9191f80 RCX: 00007f0ff9022654
RDX: 0000000000000002 RSI: 00007f0ff87e4d40 RDI: 00000000ffffff9c
RBP: 00007f0ff87e4d40 R08: 0000000000000000 R09: 000000000000000f
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002
R13: 00007ffc137b749f R14: 00007f0ff87e5300 R15: 0000000000022000
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff87a94990 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
6 locks held by kworker/0:1/13:
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc900000dfda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff88810f777190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#2: ffff88810f777190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1bc/0x45e0 drivers/usb/core/hub.c:5681
#3: ffff88810e953190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#3: ffff88810e953190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#4: ffff88810e950118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#4: ffff88810e950118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev drivers/usb/core/file.c:187 [inline]
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev+0x198/0x7e0 drivers/usb/core/file.c:156
6 locks held by kworker/1:0/21:
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc9000016fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff88810ee9b190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#2: ffff88810ee9b190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1bc/0x45e0 drivers/usb/core/hub.c:5681
#3: ffff88811dd33190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#3: ffff88811dd33190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#4: ffff88813ee8e118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#4: ffff88813ee8e118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev drivers/usb/core/file.c:187 [inline]
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev+0x198/0x7e0 drivers/usb/core/file.c:156
1 lock held by khungtaskd/27:
#0: ffffffff87a954e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6492
2 locks held by getty/1236:
#0: ffff88810f73b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
#1: ffffc900000452f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef0/0x13e0 drivers/tty/n_tty.c:2177
6 locks held by kworker/0:3/4102:
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc90001effda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff88810f813190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#2: ffff88810f813190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1bc/0x45e0 drivers/usb/core/hub.c:5681
#3: ffff888109aa6190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#3: ffff888109aa6190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#4: ffff888109c6a118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#4: ffff888109c6a118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x76/0x530 drivers/base/dd.c:983
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev drivers/usb/core/file.c:187 [inline]
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev+0x198/0x7e0 drivers/usb/core/file.c:156
6 locks held by kworker/0:8/4233:
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff888109c39138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc900019e7da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff88810f757190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#2: ffff88810f757190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1bc/0x45e0 drivers/usb/core/hub.c:5681
#3: ffff88811da9d190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#3: ffff88811da9d190 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x6ed drivers/usb/core/hub.c:2226
#4: ffff888138e9e118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#4: ffff888138e9e118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1073 [inline]
#4: ffff888138e9e118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa0/0x700 drivers/base/dd.c:1272
#5: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_deregister_dev+0xa5/0x320 drivers/usb/core/file.c:239
3 locks held by udevd/6902:
#0: ffff888116ff7088 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:236 [inline]
#0: ffff888116ff7088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x189/0x7a0 fs/kernfs/file.c:276
#1: ffff88810d297e88 (kn->active#27){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:237 [inline]
#1: ffff88810d297e88 (kn->active#27){++++}-{0:0}, at: kernfs_fop_read_iter+0x1ac/0x7a0 fs/kernfs/file.c:276
#2: ffff88810e953190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:840 [inline]
#2: ffff88810e953190 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
3 locks held by udevd/6916:
#0: ffff88810f892488 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:236 [inline]
#0: ffff88810f892488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x189/0x7a0 fs/kernfs/file.c:276
#1: ffff88813d855cb8 (kn->active#27){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:237 [inline]
#1: ffff88813d855cb8 (kn->active#27){++++}-{0:0}, at: kernfs_fop_read_iter+0x1ac/0x7a0 fs/kernfs/file.c:276
#2: ffff888109aa6190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:840 [inline]
#2: ffff888109aa6190 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
3 locks held by udevd/6917:
#0: ffff8881364aa888 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:236 [inline]
#0: ffff8881364aa888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x189/0x7a0 fs/kernfs/file.c:276
#1: ffff88810d075660 (kn->active#27){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:237 [inline]
#1: ffff88810d075660 (kn->active#27){++++}-{0:0}, at: kernfs_fop_read_iter+0x1ac/0x7a0 fs/kernfs/file.c:276
#2: ffff88811dd33190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:840 [inline]
#2: ffff88811dd33190 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
2 locks held by syz-executor.1/10126:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
#1: ffff888117d120d0 (&(sisusb->lock)){+.+.}-{3:3}, at: sisusb_open+0xb2/0x4d0 drivers/usb/misc/sisusbvga/sisusb.c:2396
2 locks held by syz-executor.1/10132:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
#1: ffff888117d120d0 (&(sisusb->lock)){+.+.}-{3:3}, at: sisusb_open+0xb2/0x4d0 drivers/usb/misc/sisusbvga/sisusb.c:2396
1 lock held by syz-executor.5/10119:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
1 lock held by syz-executor.1/11143:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
1 lock held by syz-executor.1/11145:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
1 lock held by syz-executor.1/11714:
#0: ffffffff884520d0 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x24/0x2e0 drivers/usb/core/file.c:39
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x46/0x14f lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x206/0x250 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xc18/0xf50 kernel/hung_task.c:369
kthread+0x2ea/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x1fd/0x2a0 drivers/acpi/processor_idle.c:572