The agp_generic_remove_memory function in drivers/char/agp/generic.c in the Linux kernel before 2.6.38.5 does not validate a certain start parameter, which allows local users to gain privileges or cause a denial of service (system crash) via a crafted AGPIOC_UNBIND agp_ioctl ioctl call, a different vulnerability than CVE-2011-1745.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=194b3da873fd334ef183806db751473512af29ce
openwall.com/lists/oss-security/2011/04/21/4
openwall.com/lists/oss-security/2011/04/22/7
rhn.redhat.com/errata/RHSA-2011-0927.html
www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38.5
www.securityfocus.com/bid/47843
bugzilla.redhat.com/show_bug.cgi?id=698996
lkml.org/lkml/2011/4/14/293