特権コンテナで遊んでいたら /lib/modules 配下を壊してしまったようだ。 よくわからないがこのマシンから外部に出ていくときに、疎通したりしなかったりする。 イーサネットをUSBタイプAとして受けるアダプタ BUFFALO LUA4-U3-AGTE-NBK 1 を使っていて、 それに対応するドライバが怪しい。 ログはこんな感じ。

ubuntu2004thinkpad:~$ dmesg
IPv6: ADDRCONF(NETDEV_CHANGE): enx9096f349a025: link becomes ready
usb 3-1: USB disconnect, device number 45
ax88179_178a 3-1:1.0 enx9096f349a025: unregister 'ax88179_178a' usb-0000:00:14.0-1, ASIX AX88179 USB 3.0 Gigabit Ethernet
ax88179_178a 3-1:1.0 enx9096f349a025: Failed to read reg index 0x0002: -19
ax88179_178a 3-1:1.0 enx9096f349a025: Failed to write reg index 0x0002: -19
ax88179_178a 3-1:1.0 enx9096f349a025 (unregistered): Failed to write reg index 0x0002: -19
ax88179_178a 3-1:1.0 enx9096f349a025 (unregistered): Failed to write reg index 0x0001: -19
ax88179_178a 3-1:1.0 enx9096f349a025 (unregistered): Failed to write reg index 0x0002: -19
usb 3-1: new SuperSpeed Gen 1 USB device number 46 using xhci_hcd
usb 3-1: New USB device found, idVendor=0b95, idProduct=1790, bcdDevice= 1.00
usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 3-1: Product: AX88179
usb 3-1: Manufacturer: ASIX Elec. Corp.
usb 3-1: SerialNumber: 000000000013D6
ax88179_178a 3-1:1.0 eth0: register 'ax88179_178a' at usb-0000:00:14.0-1, ASIX AX88179 USB 3.0 Gigabit Ethernet, 90:96:f3:49:a0:25
ax88179_178a 3-1:1.0 enx9096f349a025: renamed from eth0
ax88179_178a 3-1:1.0 enx9096f349a025: ax88179 - Link status is: 1
ax88179_178a 3-1:1.0 enx9096f349a025: ax88179 - Link status is: 1
IPv6: ADDRCONF(NETDEV_CHANGE): enx9096f349a025: link becomes ready
ubuntu2004thinkpad:~$ modinfo ax88179_178a
filename:       /lib/modules/5.11.0-41-generic/kernel/drivers/net/usb/ax88179_178a.ko
license:        GPL
description:    ASIX AX88179/178A based USB 3.0/2.0 Gigabit Ethernet Devices
srcversion:     6804C9DF57CD4C6DED0FF5F

最新のドライバ 2 をインストールしてことなきを得た。

ubuntu2004thinkpad:~$ tar -jxf ASIX_USB_NIC_Linux_Driver_Source_v1.1.0.tar.bz2
ubuntu2004thinkpad:~$ cd ASIX_USB_NIC_Linux_Driver_Source_v1.1.0/
ubuntu2004thinkpad:~/ASIX_USB_NIC_Linux_Driver_Source_v1.1.0$ head Readme
===============================================================================
ASIX USB3.0/2.0 Gigabit Ethernet Network Adapter
Driver Compilation & Configuration on Linux
===============================================================================
* AX88179A/772D
* AX88179/178A

ubuntu2004thinkpad:~/ASIX_USB_NIC_Linux_Driver_Source_v1.1.0$ make
ubuntu2004thinkpad:~/ASIX_USB_NIC_Linux_Driver_Source_v1.1.0$ sudo make install
ubuntu2004thinkpad:~/ASIX_USB_NIC_Linux_Driver_Source_v1.1.0$ sudo shutdown -r now
ubuntu2004thinkpad:~$ modinfo ax_usb_nic
filename:       /lib/modules/5.11.0-41-generic/kernel/drivers/net/usb/ax_usb_nic.ko
version:        1.1.0
license:        GPL
description:    ASIX USB Ethernet Controller
author:         ASIX
srcversion:     70A2F9C6480590576F9E457

ubuntu2004thinkpad:~$ dmesg |grep ax_usb_nic
ax_usb_nic: loading out-of-tree module taints kernel.
ax_usb_nic: module verification failed: signature and/or required key missing - tainting kernel
ax_usb_nic 2-1:1.0: ASIX AX88179_178A USB Ethernet Controller 1.1.0 (0.0.0.0_4.0)
usbcore: registered new interface driver ax_usb_nic
ax_usb_nic 2-1:1.0 enx9096f349a025: renamed from eth0
ax_usb_nic 2-1:1.0 enx9096f349a025: link up, 1000Mbps, full-duplex, lpa 0xC5E1