Red Hat Enterprise Linux 6.4: Important Update for Kernel Memory Issues

The kernel packages contain the Linux kernel, the core of any Linux operating system.
* It was found that the Linux kernel's implementation of vectored pipe read and write functionality did not take into account the I/O vectors that were already processed when retrying after a failed atomic access operation, potentially resulting in memory corruption due to an I/O vector array overrun. A local, unprivileged user could use this flaw to crash the system or, potentially, escalate their privileges on the system. (CVE-2015-1805, Important)
The security impact of this issue was discovered by Red Hat.
This update also fixes the following bugs:
* The backlog data could previously not be consumed when the audit_log_start() function was running even if audit_log_start() called the wait_for_auditd() function to consume it. As only auditd could consume the backlog data, audit_log_start() terminated unexpectedly. Consequently, the system became unresponsive until the backlog timeout was up. With this update, audit_log_start() no longer terminates and the system shuts down and reboots gracefully in a timely manner. (BZ#1140489)
* Direct I/O writes extending a parallel file could previously race to update the size of the file. If the writes executed in the out-of-order manner, the file size could move backwards and push a previously completed write beyond EOF, causing it to be lost. With this update, file size updates are always executed in appropriate order, thus fixing this bug. (BZ#1218497)
All kernel users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.