Pat Riehecky wrote:

>> It only seems to occur with NFS mounts served from a RHEL 5.7 x86_64 system.
>> There is no problem with unmounting mounts served from a RHEL 6.1 x86_64
>> NFS system.
[...]
> I don't have any RHEL systems, but I just spun up some SL5.7 systems.

Oh, I'm sorry; I should have said SL, not RHEL. These are all SL
systems, no RHEL involved anywhere.

> I made a 32 and 64 bit system for both 6.1 and 5.7, I then made a read
> only and read-write nfs share from the 5.7 systems.  After mounting it
> on the 6.1 systems and doing various IO, I unmounted it without
> producing a segfault.
>
> I fear I'm unable to replicate the issue.

Thanks for trying, maybe it's something peculiar to my setup.
I'm not aware of having anything unusual though.
I can just stick with nfs-utils-1.2.3-15.el6.