Reproduced the Wi-Fi failure again on kernel 7.0.0-28-generic with a
Netgear A8000 / mt7921u adapter.

During the failure, NetworkManager reported the Wi-Fi device as
unavailable and wpa_cli commands timed out. However, a direct iw scan
still succeeded and returned nearby access points, so the radio/driver
remained responsive enough to scan.

The wpa_supplicant process had only one thread and was blocked in the
kernel at:

sock_alloc_send_pskb -> packet_snd -> packet_sendmsg -> __sys_sendto

strace showed it blocked in sendto() on fd 12, an AF_PACKET socket.
Socket diagnostics identify fd 12 as the EAPOL/802.1X (0x888e) packet
socket. Its socket-memory state was:

Recv-Q=214272, r=214272, rb=212992, t=213120, tb=212992, drops=472.

NetworkManager logs also show that when NetworkManager was started, it
repeatedly attempted to create the supplicant interface, received D-Bus
Timeout was reached errors, retried five times, and then logged
supplicant interface keeps failing, giving up.

Recovery test:

Restarting wpa_supplicant only replaced the hung process, but Wi-Fi remained 
unavailable because NetworkManager had already given up creating the supplicant 
interface.
Restarting NetworkManager afterward immediately restored Wi-Fi connectivity and 
normal scanning.
No mt7921u module unload/reload, USB reset/unplug, or reboot was required.

Attached:

wifi-hang-extra-20260812-123015.txt
wpa-strace-20260812-123015.124865.txt
wifi-debug-full-20260812-123527.txt

** Attachment added: "wifi-hang-20260812.zip"
   
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161448/+attachment/5991576/+files/wifi-hang-20260812.zip

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https://bugs.launchpad.net/bugs/2161448

Title:
  mt7921u: USB Wi-Fi enters unrecoverable state after prolonged uptime;
  NetworkManager/supplicant stalls followed by USB disconnect deadlock

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