(RHSA-2012:0517) Moderate: kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issue:

• A flaw was found in the Linux kernel in the way splitting two extents in
  ext4_ext_convert_to_initialized() worked. A local, unprivileged user with
  the ability to mount and unmount ext4 file systems could use this flaw to
  cause a denial of service. (CVE-2011-3638, Moderate)

Red Hat would like to thank Zheng Liu for reporting this issue.

This update also fixes the following bug:

• Starting with Red Hat Enterprise Linux 5.6, all devices that used the
  ixgbe driver would stop stripping VLAN tags when the device entered
  promiscuous mode. Placing a device in a bridge group causes the device to
  enter promiscuous mode. This caused various issues under certain
  configurations of bridging and VLANs. A patch has been provided to address
  this issue and the devices now properly strip VLAN tags in the driver
  whether in promiscuous mode or not. (BZ#809790)

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. The system must be rebooted for this
update to take effect.