Because of a change from 2.6.8-rc3 to 2.6.8-rc4, nfs access can lock up the server. Please see the following link for the bug report in the kernel's bugzilla. http://bugme.osdl.org/show_bug.cgi?id=3190
Created attachment 37235 [details, diff] Fixes decreasing of now unsigned loop variable 'len'
Great, but this isn't a gentoo specific bug, it's a kernel.org issue. So I'm closing this.