A while back, cc n wrote:
Our nfs server crashs occasionally. Any idea to solve the problem? Thanks!
and attached a kernel stack trace.
Have you run a full memtest86 against the box?
Have you put this in bugzilla.redhat.com?
It could be either hardware or software. If it's software, it needs to go in Bugzilla so the Fedora / Red Hat kernel team can keep track of it.
If it's hardware, it smells like memory (or possibly motherboard / CPU / network card). You should start trying to check these as much as possible.
HTH,
James.