Description of problem:
libvirt occasionally fails to connect to the qemu monitor,
process exited while connecting to monitor: fread() failed
Version-Release number of selected component (if applicable):
Rare. About 3% of failures were caused by this problem in my tests.
Steps to Reproduce:
1. Run virt-df repeatedly.
Marking as dupe. For background, read this thread:
*** This bug has been marked as a duplicate of bug 921135 ***