We recently applied a large amount of patches to bring our workstations (HP 9400 / Z800's) from RHEL 5.5 to 5.7 and have been running into intermittent freezing during normal use.
When this occurs the kernel becomes unresponsive, I am unable to switch virtual terminals, networking is dead (can't ping / ssh in), and we resort to issuing SysRQ commands to gather info. There is nothing useful in /var/log/messages or sar reports.
We currently have a ticket open with Redhat support and since sent in a vmcore dump.
My question is, has anyone else come across this issue recently? If so, we're the circumstances similar?