Another day, another lockup. Apple, are you listening? I either need a fix from you or some instructions on how to determine the stack trace. With that, it should be possible to determine which semaphore is being waited on and then figure out where it was acquired in the USB mouse driver code. P.S. to be clear: 13.7.8 did not resolve this problem.

Happened again -- only one day apart. This time, there was a 13.7.8 install to do, so I did that as my reboot. First, it would not work with my second monitor (the "displays" in system settings saw it, but no way to connect), so I rebooted again. only to be offered an update installation. The update didn't take. Rebooted into a power down, pressed the power button. The second display didn't activate again, so another reboot. I'm up and running. OH, just to clarify, whenever this happens, I plug in a generic USB mouse. USB Keyboard: works fine, USB mouse (of any sort) dead. I conclude that it is the USB mouse driver. with 13.7.8, I surely hope this problem goes away.

kill -ABRT didn't trigger a core dump, so again no diagnostics

Any hints about how to get a crash dump or (better) a dump of the mouse driver & its data?