Re: [Testbed-admins] kernel memory leaks in FreeBSD NFS (patched)

[Robert P Ricci <ricci@cs.utah.edu>]

Aha!

We do periodically run out of memory on our ops, and this certainly
could be it.

Nice detective work!

Thus spake Mike Ryan on Thu, Dec 03, 2009 at 02:02:05PM -0800:
> tb-admins:
> 
> The DETER team recently uncovered a bug in FreeBSD's NFS code that
> causes the kernel to leak memory. If left untreated this bug can exhaust
> kernel memory, causing a panic. As far as we can tell, this affects all
> versions of FreeBSD currently in production.
> 
> We submitted a patch which has been pushed into FreeBSD CVS. The file
> affected is src/sys/nfsserver/nfs_serv.c:
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/nfsserver/nfs_serv.c?sortby=date 
> 
> 
> An NFS client which tries to delete an inexistent file will trigger the
> bug. This can result from rebooting the ops node while experiments are
> running.
> 
> To test if you've been affected, on your ops node run:
> 
> $ nfsstat | grep -A1 faults
> Server Faults
>             0
> 
> If this number is greater than zero (or worse, climbing), then your NFS
> server has been leaking memory. Regardless, we recommend patching your
> systems.
> 
> 
> For more details about the problem, see the original PR:
> http://www.freebsd.org/cgi/query-pr.cgi?pr=140853
> 
> Mike Ryan
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