From Ted Unangst@21:1/5 to All on Tue Sep 29 13:25:01 2015
Earlier this month, kettenis identified a bug in uvm from an incompletely reverted change. Clearing the wrong bit on a page would sometimes result in
the page queues being corrupted, and then eventually the system would crash or panic.
This issue affects 5.7 and the forthcoming 5.8 release.
Patches are available. Apply the patch, rebuild the kernel, and reboot.