RHSA-2015:0783: Important: kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linuxoperating system. It was found that the Linux kernel's Infiniband subsystem did not properly sanitize input parameters while registering memory regions fromuser space via the (u)verbs API. A local user with access to a/dev/infiniband/uverbsX device could use this flaw to crash the system or,potentially, escalate their privileges on the system. (CVE-2014-8159,Important) An insufficient bound checking flaw was found in the Xen hypervisor's implementation of acceleration support for the "REP MOVS" instructions.A privileged HVM guest user could potentially use this flaw to crash thehost. (CVE-2014-8867, Important)Red Hat would like to thank Mellanox for reporting CVE-2014-8159, and theXen project for reporting CVE-2014-8867.This update also fixes the following bugs: Under memory pressure, cached data was previously flushed to the backing server using the PID of the thread responsible for flushing the data in theServer Message Block (SMB) headers instead of the PID of the thread whichactually wrote the data. As a consequence, when a file was locked by thewriting thread prior to writing, the server considered writes by the threadflushing the pagecache as being a separate process from writing to a lockedfile, and thus rejected the writes. In addition, the data to be written wasdiscarded. This update ensures that the correct PID is sent to the server,and data corruption is avoided when data is being written from a clientunder memory pressure. (BZ#1169304) This update adds support for new cryptographic hardware in toleration mode for IBM System z. (BZ#1182522)All kernel users are advised to upgrade to these updated packages, whichcontain backported patches to correct these issues. The system must berebooted for this update to take effect.