cdc_mbim 1-1:1.0: setting tx_max = 48
cdc_mbim 1-1:1.0: cdc-wdm0: USB WDM device
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:0/9 is trying to acquire lock:
ffffffff8f4f9500 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:316 [inline]
ffffffff8f4f9500 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4673 [inline]
ffffffff8f4f9500 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:5011 [inline]
ffffffff8f4f9500 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x5e/0x670 mm/slub.c:5676

but task is already holding lock:
ffffffff8fd8cc58 (gdp_mutex){+.+.}-{4:4}, at: get_device_parent+0x173/0x3a0 drivers/base/core.c:3338

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #9 (gdp_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:561 [inline]
       mutex_lock_nested+0x55/0x1d0 kernel/locking/rtmutex_api.c:580
       get_device_parent+0x173/0x3a0 drivers/base/core.c:3338
       device_add+0x2d4/0xb80 drivers/base/core.c:3685
       device_create_groups_vargs drivers/base/core.c:4458 [inline]
       device_create+0x269/0x300 drivers/base/core.c:4497
       msr_device_create+0x33/0x50 arch/x86/kernel/msr.c:254
       cpuhp_invoke_callback+0x434/0x810 kernel/cpu.c:194
       cpuhp_thread_fun+0x362/0x780 kernel/cpu.c:1109
       smpboot_thread_fn+0x5f8/0xb30 kernel/smpboot.c:162
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #8 (cpuhp_state-up){+.+.}-{0:0}:
       cpuhp_lock_acquire kernel/cpu.c:103 [inline]
       cpuhp_thread_fun+0x127/0x780 kernel/cpu.c:1086
       smpboot_thread_fn+0x5f8/0xb30 kernel/smpboot.c:162
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #7 (cpu_hotplug_lock){++++}-{0:0}:
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
       cpus_read_lock+0x3d/0x160 kernel/cpu.c:490
       static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
       fl_create net/ipv6/ip6_flowlabel.c:451 [inline]
       ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:655 [inline]
       ipv6_flowlabel_opt+0x15ed/0x2450 net/ipv6/ip6_flowlabel.c:770
       do_ipv6_setsockopt+0x9cb/0x2960 net/ipv6/ipv6_sockglue.c:843
       ipv6_setsockopt+0x59/0x170 net/ipv6/ipv6_sockglue.c:880
       do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2399
       __sys_setsockopt net/socket.c:2424 [inline]
       __do_sys_setsockopt net/socket.c:2430 [inline]
       __se_sys_setsockopt net/socket.c:2427 [inline]
       __x64_sys_setsockopt+0x143/0x1b0 net/socket.c:2427
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x120 net/core/sock.c:3908
       lock_sock include/net/sock.h:1717 [inline]
       inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:911
       nbd_mark_nsock_dead+0x2cb/0x550 drivers/block/nbd.c:319
       sock_shutdown+0x15e/0x260 drivers/block/nbd.c:420
       nbd_clear_sock+0x24/0x170 drivers/block/nbd.c:1463
       nbd_config_put+0x487/0x7f0 drivers/block/nbd.c:1492
       nbd_genl_connect+0x19c1/0x1cd0 drivers/block/nbd.c:2319
       genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
       genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
       genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
       netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2576
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
       netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
       netlink_unicast+0x90c/0xac0 net/netlink/af_netlink.c:1361
       netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920
       sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800
       __sock_sendmsg net/socket.c:818 [inline]
       ____sys_sendmsg+0x565/0x870 net/socket.c:2715
       ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769
       __sys_sendmsg net/socket.c:2801 [inline]
       __do_sys_sendmsg net/socket.c:2806 [inline]
       __se_sys_sendmsg net/socket.c:2804 [inline]
       __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2804
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:561 [inline]
       mutex_lock_nested+0x55/0x1d0 kernel/locking/rtmutex_api.c:580
       nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
       nbd_queue_rq+0x373/0xff0 drivers/block/nbd.c:1207
       blk_mq_dispatch_rq_list+0x4af/0x1a00 block/blk-mq.c:2131
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xd45/0x1590 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
       blk_mq_run_work_fn+0x16a/0x2f0 block/blk-mq.c:2546
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #4 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:561 [inline]
       mutex_lock_nested+0x55/0x1d0 kernel/locking/rtmutex_api.c:580
       nbd_queue_rq+0xc1/0xff0 drivers/block/nbd.c:1199
       blk_mq_dispatch_rq_list+0x4af/0x1a00 block/blk-mq.c:2131
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xd45/0x1590 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
       blk_mq_run_work_fn+0x16a/0x2f0 block/blk-mq.c:2546
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync include/linux/srcu.h:225 [inline]
       __synchronize_srcu+0xca/0x2f0 kernel/rcu/srcutree.c:1662
       elevator_switch+0x1e8/0x7b0 block/elevator.c:576
       elevator_change+0x2fa/0x480 block/elevator.c:681
       elevator_set_default+0x375/0x440 block/elevator.c:754
       blk_register_queue+0x404/0x4f0 block/blk-sysfs.c:992
       __add_disk+0x6b8/0xdb0 block/genhd.c:531
       add_disk_fwnode+0x100/0x3a0 block/genhd.c:600
       add_disk include/linux/blkdev.h:801 [inline]
       nbd_dev_add+0x733/0xb60 drivers/block/nbd.c:2026
       nbd_init+0x168/0x1f0 drivers/block/nbd.c:2743
       do_one_initcall+0x250/0x870 init/main.c:1423
       do_initcall_level+0x10a/0x1a0 init/main.c:1485
       do_initcalls+0x59/0xa0 init/main.c:1501
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1736
       kernel_init+0x22/0x1d0 init/main.c:1626
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:561 [inline]
       mutex_lock_nested+0x55/0x1d0 kernel/locking/rtmutex_api.c:580
       elevator_change+0x1af/0x480 block/elevator.c:679
       elv_iosched_store+0x504/0x630 block/elevator.c:826
       queue_attr_store+0x207/0x2b0 block/blk-sysfs.c:906
       kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x61e/0xbb0 fs/read_write.c:687
       ksys_write+0x156/0x270 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#66){++++}-{0:0}:
       blk_alloc_queue+0x54c/0x690 block/blk-core.c:505
       blk_mq_alloc_queue block/blk-mq.c:4433 [inline]
       __blk_mq_alloc_disk+0x194/0x390 block/blk-mq.c:4480
       null_add_dev+0xe8a/0x1d70 drivers/block/null_blk/main.c:2017
       null_create_dev drivers/block/null_blk/main.c:2114 [inline]
       null_init+0x1e3/0x390 drivers/block/null_blk/main.c:2178
       do_one_initcall+0x250/0x870 init/main.c:1423
       do_initcall_level+0x10a/0x1a0 init/main.c:1485
       do_initcalls+0x59/0xa0 init/main.c:1501
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1736
       kernel_init+0x22/0x1d0 init/main.c:1626
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       __fs_reclaim_acquire mm/page_alloc.c:4365 [inline]
       fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4379
       might_alloc include/linux/sched/mm.h:316 [inline]
       slab_pre_alloc_hook mm/slub.c:4673 [inline]
       slab_alloc_node mm/slub.c:5011 [inline]
       __kmalloc_cache_noprof+0x5e/0x670 mm/slub.c:5676
       _kmalloc_noprof include/linux/slab.h:991 [inline]
       _kzalloc_noprof include/linux/slab.h:1312 [inline]
       class_dir_create_and_add drivers/base/core.c:3295 [inline]
       get_device_parent+0x25c/0x3a0 drivers/base/core.c:3355
       device_add+0x2d4/0xb80 drivers/base/core.c:3685
       wwan_create_dev+0x17e/0x260 drivers/net/wwan/wwan_core.c:270
       wwan_create_port+0xf4/0xd20 drivers/net/wwan/wwan_core.c:640
       wdm_wwan_init+0x80/0x180 drivers/usb/class/cdc-wdm.c:940
       wdm_create+0x11fe/0x1600 drivers/usb/class/cdc-wdm.c:1127
       usb_cdc_wdm_register+0x33/0x60 drivers/usb/class/cdc-wdm.c:1207
       cdc_mbim_bind+0x3da/0x630 drivers/net/usb/cdc_mbim.c:168
       usbnet_probe+0xae3/0x2b00 drivers/net/usb/usbnet.c:1812
       usb_probe_interface+0x751/0xe00 drivers/usb/core/driver.c:399
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x254/0xae0 drivers/base/dd.c:707
       __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869
       driver_probe_device+0x4f/0x240 drivers/base/dd.c:899
       __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027
       bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:503
       __device_attach+0x2c0/0x430 drivers/base/dd.c:1131
       device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190
       __bus_probe_device+0x129/0x220 drivers/base/bus.c:617
       device_add+0x7d7/0xb80 drivers/base/core.c:3776
       usb_set_configuration+0x1bb5/0x2260 drivers/usb/core/message.c:2280
       usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
       usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:293
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x254/0xae0 drivers/base/dd.c:707
       __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869
       driver_probe_device+0x4f/0x240 drivers/base/dd.c:899
       __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027
       bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:503
       __device_attach+0x2c0/0x430 drivers/base/dd.c:1131
       device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190
       __bus_probe_device+0x129/0x220 drivers/base/bus.c:617
       device_add+0x7d7/0xb80 drivers/base/core.c:3776
       usb_new_device+0x99a/0x1680 drivers/usb/core/hub.c:2713
       hub_port_connect drivers/usb/core/hub.c:5585 [inline]
       hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
       port_event drivers/usb/core/hub.c:5889 [inline]
       hub_event+0x28cf/0x4cf0 drivers/usb/core/hub.c:5971
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> cpuhp_state-up --> gdp_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(gdp_mutex);
                               lock(cpuhp_state-up);
                               lock(gdp_mutex);
  lock(fs_reclaim);

 *** DEADLOCK ***

locks held by kworker/0:0/9: 7, last CPU#0:
 #0: ffff88801bb19140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801bb19140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801bb19140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #0: ffff88801bb19140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #2: ffff88802af88210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
 #2: ffff88802af88210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5917
 #3: ffff888035926210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
 #3: ffff888035926210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1106
 #4: ffff8880316651d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
 #4: ffff8880316651d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1106
 #5: ffffffff90023558 (wwan_register_lock){+.+.}-{4:4}, at: wwan_create_dev+0x1e/0x260 drivers/net/wwan/wwan_core.c:241
 #6: ffffffff8fd8cc58 (gdp_mutex){+.+.}-{4:4}, at: get_device_parent+0x173/0x3a0 drivers/base/core.c:3338

stack backtrace:
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 __fs_reclaim_acquire mm/page_alloc.c:4365 [inline]
 fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4379
 might_alloc include/linux/sched/mm.h:316 [inline]
 slab_pre_alloc_hook mm/slub.c:4673 [inline]
 slab_alloc_node mm/slub.c:5011 [inline]
 __kmalloc_cache_noprof+0x5e/0x670 mm/slub.c:5676
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 class_dir_create_and_add drivers/base/core.c:3295 [inline]
 get_device_parent+0x25c/0x3a0 drivers/base/core.c:3355
 device_add+0x2d4/0xb80 drivers/base/core.c:3685
 wwan_create_dev+0x17e/0x260 drivers/net/wwan/wwan_core.c:270
 wwan_create_port+0xf4/0xd20 drivers/net/wwan/wwan_core.c:640
 wdm_wwan_init+0x80/0x180 drivers/usb/class/cdc-wdm.c:940
 wdm_create+0x11fe/0x1600 drivers/usb/class/cdc-wdm.c:1127
 usb_cdc_wdm_register+0x33/0x60 drivers/usb/class/cdc-wdm.c:1207
 cdc_mbim_bind+0x3da/0x630 drivers/net/usb/cdc_mbim.c:168
 usbnet_probe+0xae3/0x2b00 drivers/net/usb/usbnet.c:1812
 usb_probe_interface+0x751/0xe00 drivers/usb/core/driver.c:399
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:707
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:899
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:503
 __device_attach+0x2c0/0x430 drivers/base/dd.c:1131
 device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190
 __bus_probe_device+0x129/0x220 drivers/base/bus.c:617
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_set_configuration+0x1bb5/0x2260 drivers/usb/core/message.c:2280
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:707
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:899
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:503
 __device_attach+0x2c0/0x430 drivers/base/dd.c:1131
 device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190
 __bus_probe_device+0x129/0x220 drivers/base/bus.c:617
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_new_device+0x99a/0x1680 drivers/usb/core/hub.c:2713
 hub_port_connect drivers/usb/core/hub.c:5585 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
 port_event drivers/usb/core/hub.c:5889 [inline]
 hub_event+0x28cf/0x4cf0 drivers/usb/core/hub.c:5971
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
wwan wwan0: port wwan0mbim0 attached
cdc_mbim 1-1:1.0 wwan0: register 'cdc_mbim' at usb-dummy_hcd.0-1, CDC MBIM, 52:a4:c5:78:0b:91
usb 1-1: USB disconnect, device number 3
cdc_mbim 1-1:1.0 wwan0: unregister 'cdc_mbim' usb-dummy_hcd.0-1, CDC MBIM
wwan wwan0: port wwan0mbim0 disconnected