my problem is my Raspbian (with PREEMPT-RT patch) is freezing after performing sudo apt-get update.
Is there any logs or anyway to know what happened to Raspbian after this update. so that I can figure out what makes conflict with the PREEMPT-RT patch.
p.s: in Raspberry website it is mentioned that downloaded package files (.deb files) are kept in /var/cache/apt/archives. but I believe that there are other changes in the system that caused this freezing.