RHSA-2014:1943: Moderate: kernel-rt security, bug fix, and enhancement update

The kernel-rt packages contain the Linux kernel, the core of any Linuxoperating system.A denial of service flaw was found in the way the Linux kernel's XFS filesystem implementation ordered directory hashes under certain conditions.A local attacker could use this flaw to corrupt the file system by creatingdirectories with colliding hash values, potentially resulting in a systemcrash. (CVE-2014-7283, Moderate)An out-of-bounds memory access flaw was found in the syscall tracingfunctionality of the Linux kernel's perf subsystem. A local, unprivilegeduser could use this flaw to crash the system. (CVE-2014-7825, Moderate)An out-of-bounds memory access flaw was found in the syscall tracingfunctionality of the Linux kernel's ftrace subsystem. On a system withftrace syscall tracing enabled, a local, unprivileged user could use thisflaw to crash the system, or escalate their privileges. (CVE-2014-7826,Moderate)Red Hat would like to thank Robert Święcki for reporting CVE-2014-7825 andCVE-2014-7826.The kernel-rt packages have been upgraded to upstream version 3.10.58,which provides a number of bug fixes and enhancements over the previousversion. (BZ#1158105)This update also fixes the following bugs: Automatic NUMA balancing on a low priority thread could cause memory contention with a high priority thread running in the same process.This contention could trigger poor realtime performance on the system.In order to avoid this potential memory contention, the MRG Realtime kernelnow disables NUMABALANCINGDEFAULTENABLED. (BZ#1158940) When tracing a bug, WARN() functions could flood the ring buffer making the trace useless or even overflowing the ring buffer. To address thisissue, a traceoffonwarning option was added to the kernel command lineand as a sysctl option. This option disables the writing of the warningmessages to the ring buffer, which results in a cleaner trace fordebugging. (BZ#1155200)In addition, this update adds the following enhancement: Support for XHCI (USB 3) is now enabled in the MRG Realtime kernel. (BZ#1134095)All kernel-rt users are advised to upgrade to these updated packages, whichcontain correct these issues and add these enhancements. The system must berebooted for this update to take effect.