Through a quick glance, nothing suspicious are shown regarding the graphics. So we can't say that it's a GPU issue from the logs. Both logs ended with a normal DRM debug message, but there was no sign of reboot behavior at all; usually no matter whether it's triggered by user or by kernel itself, the reboot procedure must have taken place. Didn't you get any log after that point? That is, isn't the reboot recorded in the kernel log at all?