There are three mailing lists for gem5:
We maintain archives of our mailing list.
The gem5-dev mail archive can be found here.
The gem5-users mail archive can be found here.
The gem5-announce mail archive can be found here.
Stack Overflow can be used to crowd-source solutions to gem5 related problems. The Stack Overflow
gem5 tag should be used: https://stackoverflow.com/questions/tagged/gem5). Please make sure that your question complies with the site guidelines before posting. Interested users can opt to receive email notifications for such questions as explained at https://meta.stackexchange.com/questions/25224/email-notifications-for-new-questions-matching-specific-tags).