The nlmclnt_mark_reclaim in clntlock.c in NFS lockd in Linux kernel before 2.6.16 allows remote attackers to cause a denial of service (process crash) and deny access to NFS exports via unspecified vectors that trigger a kernel oops (null dereference) and a deadlock.
http://marc.info/?l=linux-kernel&m=113476665626446&w=2
http://marc.info/?l=linux-kernel&m=113494474208973&w=2
http://rhn.redhat.com/errata/RHSA-2007-0488.html
http://support.avaya.com/elmodocs2/security/ASA-2007-287.htm
http://www.mandriva.com/security/advisories?name=MDKSA-2007:012