Red Hat Enterprise Linux 6: RHSA-2014:1843-01 Important Kernel Fix

The kernel packages contain the Linux kernel, the core of any Linux operating system.
* A race condition flaw was found in the way the Linux kernel's KVM subsystem handled PIT (Programmable Interval Timer) emulation. A guest user who has access to the PIT I/O ports could use this flaw to crash the host. (CVE-2014-3611, Important)
* A memory corruption flaw was found in the way the USB ConnectTech WhiteHEAT serial driver processed completion commands sent via USB Request Blocks buffers. An attacker with physical access to the system could use this flaw to crash the system or, potentially, escalate their privileges on the system. (CVE-2014-3185, Moderate)
* It was found that the Linux kernel's KVM subsystem did not handle the VM exits gracefully for the invept (Invalidate Translations Derived from EPT) and invvpid (Invalidate Translations Based on VPID) instructions. On hosts with an Intel processor and invept/invppid VM exit support, an unprivileged guest user could use these instructions to crash the guest. (CVE-2014-3645, CVE-2014-3646, Moderate)
Red Hat would like to thank Lars Bull of Google for reporting CVE-2014-3611, and the Advanced Threat Research team at Intel Security for reporting CVE-2014-3645 and CVE-2014-3646.
This update also fixes the following bugs:
* This update fixes several race conditions between PCI error recovery callbacks and potential calls of the ifup and ifdown commands in the tg3 driver. When triggered, these race conditions could cause a kernel crash. (BZ#1142570)
* Previously, GFS2 failed to unmount a sub-mounted GFS2 file system if its parent was also a GFS2 file system. This problem has been fixed by adding the appropriate d_op->d_hash() routine call for the last component of the mount point path in the path name lookup mechanism code (namei). (BZ#1145193)
* Due to previous changes in the virtio-net driver, a Red Hat Enterprise Linux 6.6 guest was unable to boot with the "mgr_rxbuf=off" option specified. This was caused by providing the page_to_skb() function with an incorrect packet length in the driver's Rx path. This problem has been fixed and the guest in the described scenario can now boot successfully. (BZ#1148693)
* When using one of the newer IPSec Authentication Header (AH) algorithms with Openswan, a kernel panic could occur. This happened because the maximum truncated ICV length was too small. To fix this problem, the MAX_AH_AUTH_LEN parameter has been set to 64. (BZ#1149083)
* A bug in the IPMI driver caused the kernel to panic when an IPMI interface was removed using the hotmod script. The IPMI driver has been fixed to properly clean the relevant data when removing an IPMI interface. (BZ#1149578)
* Due to a bug in the IPMI driver, the kernel could panic when adding an IPMI interface that was previously removed using the hotmod script. This update fixes this bug by ensuring that the relevant shadow structure is initialized at the right time. (BZ#1149580)
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.