The restore_fpu_checking function in arch/x86/include/asm/fpu-internal.h in the Linux kernel before 3.12.8 on the AMD K7 and K8 platforms does not clear pending exceptions before proceeding to an EMMS instruction, which allows local users to cause a denial of service (task kill) or possibly gain privileges via a crafted application.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=26bef1318adc1b3a530ecc807ef99346db2aa8b0
lists.fedoraproject.org/pipermail/package-announce/2014-January/126858.html
lists.fedoraproject.org/pipermail/package-announce/2014-January/126874.html
www.halfdog.net/Security/2013/Vm86SyscallTaskSwitchKernelPanic/
www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.12.8
www.mandriva.com/security/advisories?name=MDVSA-2014:038
www.openwall.com/lists/oss-security/2014/01/14/1
www.securityfocus.com/bid/64781
www.securitytracker.com/id/1029592
www.ubuntu.com/usn/USN-2113-1
www.ubuntu.com/usn/USN-2117-1
www.ubuntu.com/usn/USN-2133-1
www.ubuntu.com/usn/USN-2134-1
www.ubuntu.com/usn/USN-2135-1
www.ubuntu.com/usn/USN-2136-1
www.ubuntu.com/usn/USN-2138-1
www.ubuntu.com/usn/USN-2139-1
www.ubuntu.com/usn/USN-2141-1
bugzilla.redhat.com/show_bug.cgi?id=1052914
github.com/torvalds/linux/commit/26bef1318adc1b3a530ecc807ef99346db2aa8b0
lkml.org/lkml/2014/1/9/637