KVM (Kernel-based Virtual Machine) is a full virtualization solution forLinux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built forthe standard Red Hat Enterprise Linux kernel.On x86 platforms, the do_insn_fetch() function did not limit the amount ofinstruction bytes fetched per instruction. Users in guest operating systemscould leverage this flaw to cause large latencies on SMP hosts that couldlead to a local denial of service on the host operating system. Thisupdate fixes this issue by imposing the architecturally-defined 15 bytelength limit for instructions. (CVE-2009-4031)This update also fixes the following bugs:By default, guests managed by Red Hat Enterprise Virtualization use the"werror=stop" option. This option is not used by default for guests managedby libvirt. (BZ#537334, BZ#540406)All KVM users should upgrade to these updated packages, which containbackported patches to resolve these issues. Note: The procedure in theSolution section must be performed before this update will take effect.