When samba panics and gives a backtrace it references the non-existent file BUGS.txt. BUGS.txt is referenced in: source/lib/fault.c source/smbd/process_thread.c A sample BUGS.txt might be: Samba 4 is still feature incomplete. If you are using it for anything other then education you are insane. Known major missing functionality: * Pretty much everything...
Fixed in current SVN.