In https://gem5-review.googlesource.com/c/public/gem5/+/52047 inst.pc was changed from an object to a pointer. It is possible that this pointer is null (e.g., if there is an interrupt and there is a bubble). Make sure to check that it's not null before printing. I believe that other places this pointer is dereferenced without an explicit null check are safe, but I'm not certain. Should fix #97 Change-Id: Idbe246cfdb62d4d75416d41b451fb3c076233bbc