Sometime back in January I submitted the then-current Xen4CentOS dom0 package to build in the CBS for C6, and it worked out of the box: https://cbs.centos.org/koji/buildinfo?buildID=601 After finishing up my mad month of writing slides, my holiday, and then clearing my developer backlog, I tried again with the most recent kernel version, and it failed: https://cbs.centos.org/koji/buildinfo?buildID=851 I looked at a diff between the two specfiles, and couldn't see anything that might have prompted this change; so I went back to try to build the same SRPM I built back in January; and it also failed in exactly the same way: https://cbs.centos.org/koji/taskinfo?taskID=8943 I did subsequently build a new set of xen packages, so it's not an issue with the build system in general, just an issue with the kernel package. The actual error message is this one: DEBUG util.py:333: Executing command: ['/usr/bin/yum', '--installroot', '/var/lib/mock/virt6-el6-build-1391-2327/root/', 'groupinstall', 'build', '--setopt=tsflags=nocontexts'] with env {'LANG': 'en_GB', 'TERM': 'vt100', 'SHELL': '/bin/bash', 'LC_MESSAGES': 'C', 'PROMPT_COMMAND': 'echo -n "<mock-chroot>"', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'HOME': '/builddir', 'HOSTNAME': 'mock'} DEBUG util.py:283: Error: Package: glibc-headers-2.12-1.149.el6.i686 (build) DEBUG util.py:283: Requires: kernel-headers >= 2.2.1 DEBUG util.py:283: You could try using --skip-broken to work around the problem DEBUG util.py:283: You could try running: rpm -Va --nofiles --nodigest DEBUG util.py:283: Error: Package: glibc-headers-2.12-1.149.el6.i686 (build) DEBUG util.py:283: Requires: kernel-headers DEBUG util.py:373: Child return code was: 1 I feel a bit dumb here, but I really have no idea what koji or mock are doing, so I have no real idea how to proceed to debug what's going on here. Can anyone give me a hand? -George