So the first log you provided is about the crash reporter reporting the crash, not much info in there apart from you getting segfault.
The second is somewhat normal and you would not need those in particular.
Can you post the full log somewhere? /home/myubuntu/UnrealEngine/Engine/Saved/Logs/UE4-CRC.log or the entire output you get into the console?
Also does this happen when launching the engine itself or when opening a project?