I have built a fresh version of Buster.
I have a ZTE M833V usb dongle plugged into my Raspberry Pi3+.
I have observed hangs only during boot after usb_modeswitch for the dongle. (But the usb_modeswitch log indicates it completed successfully.)
I have a script that I run at boot that looks to see if the dongle is "successfully mounted" within a minute and if it is, it reboots. If the dongle is not mounted, the system is effectively hung and I cannot lsusb, or reset the device, or even reboot. The problem occurs on 5%-40% of boots. Unfortunately, it does not occur fully repeatably.
I am attaching two /var/log/messages logs. One is from a successful boot and you can see that /media/pi/ZTEMODEM is mounted. The other is from a failed boot and you can see that there are kernel exceptions and tracebacks every minute.
I have also observed that unplugging the dongle and replugging it in generally allows for the system to continue, because a USB_DISCONNECT is seen. But I cannot figure out how to force that behavior in software since my attempts to reset the device hang.
I am at a loss as to how to proceed. Any thoughts?
Is this even the right place to report these kinds of issues?