Comment 25 for bug 1940377

After debug, this issue is not related to kernel. cdc_ether was unregistered by usb-modeswitch.
After I installed the old verison of usb-modeswitch, this issue is fixed, it looks like a regression.

Aug 30 05:54:32 u-ThinkPad-L460 kernel: cdc_ether 1-9:2.0 wwan0: register 'cdc_ether' at usb-0000:00:14.0-9, Mobile Broadband Network Device, 02:1e:10:1f:00:00
Aug 30 05:54:32 u-ThinkPad-L460 kernel: usbcore: registered new interface driver cdc_ether
Aug 30 05:54:32 u-ThinkPad-L460 kernel: cdc_ether 1-9:2.0 wwx021e101f0000: renamed from wwan0
Aug 30 05:54:33 u-ThinkPad-L460 kernel: cdc_ether 1-9:2.0 wwx021e101f0000: unregister 'cdc_ether' usb-0000:00:14.0-9, Mobile Broadband Network Device