Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
DEBUG util.py:556:  Executing command: ['userdel', '-f', 'mockbuild', '--prefix', '/var/lib/mock/f40-build-59048254-6570588/root'] with env {'TERM': 'vt100', 'SHELL': '/bin/sh', 'HOME': '/builddir', 'HOSTNAME': 'mock', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'LANG': 'C.UTF-8'} and shell False
DEBUG util.py:459:  userdel: user 'mockbuild' does not exist
DEBUG util.py:608:  Child return code was: 6
DEBUG util.py:634:  child environment: None
DEBUG util.py:556:  Executing command: ['groupdel', 'mock', '--prefix', '/var/lib/mock/f40-build-59048254-6570588/root'] with env {'TERM': 'vt100', 'SHELL': '/bin/sh', 'HOME': '/builddir', 'HOSTNAME': 'mock', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'LANG': 'C.UTF-8'} and shell False
DEBUG util.py:459:  groupdel: group 'mock' does not exist
DEBUG util.py:608:  Child return code was: 6
DEBUG util.py:634:  child environment: None
DEBUG util.py:556:  Executing command: ['groupadd', 'mock', '-g', '425', '--prefix', '/var/lib/mock/f40-build-59048254-6570588/root'] with env {'TERM': 'vt100', 'SHELL': '/bin/sh', 'HOME': '/builddir', 'HOSTNAME': 'mock', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'LANG': 'C.UTF-8'} and shell False
DEBUG util.py:608:  Child return code was: 0
DEBUG util.py:634:  child environment: None
DEBUG util.py:556:  Executing command: ['useradd', 'mockbuild'
User was not detected and was created later, so we can rule an account permissions/rbac issue out.

 SIGIOT is denoted as 4 also known as SIGABRT, used when a program deliberately terminates itself due to an internal error.