(RHSA-2010:0670) Important: 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 issues:

• When an application has a stack overflow, the stack could silently
  overwrite another memory mapped area instead of a segmentation fault
  occurring, which could cause an application to execute arbitrary code,
  possibly leading to privilege escalation. It is known that the X Window
  System server can be used to trigger this flaw. (CVE-2010-2240, Important)

• A miscalculation of the size of the free space of the initial directory
  entry in a directory leaf block was found in the Linux kernel Global File
  System 2 (GFS2) implementation. A local, unprivileged user with write
  access to a GFS2-mounted file system could perform a rename operation on
  that file system to trigger a NULL pointer dereference, possibly resulting
  in a denial of service or privilege escalation. (CVE-2010-2798, Important)

Red Hat would like to thank the X.Org security team for reporting
CVE-2010-2240, with upstream acknowledging Rafal Wojtczuk as the original
reporter; and Grant Diffey of CenITex for reporting CVE-2010-2798.

This update also fixes the following bugs:

• Problems receiving network traffic correctly via a non-standard layer 3
  protocol when using the ixgbe driver. This update corrects this issue.
  (BZ#618275)

• A bug was found in the way the megaraid_sas driver (for SAS based RAID
  controllers) handled physical disks and management IOCTLs. All physical
  disks were exported to the disk layer, allowing an oops in
  megasas_complete_cmd_dpc() when completing the IOCTL command if a timeout
  occurred. One possible trigger for this bug was running “mkfs”. This update
  resolves this issue by updating the megaraid_sas driver to version 4.31.
  (BZ#619363)

• Previously, Message Signaled Interrupts (MSI) resulted in PCI bus writes
  to mask and unmask the MSI IRQ for a PCI device. These unnecessary PCI bus
  writes resulted in the serialization of MSIs, leading to poor performance
  on systems with high MSI load. This update adds a new kernel boot
  parameter, msi_nolock, which forgoes the PCI bus writes and allows for
  better simultaneous processing of MSIs. (BZ#621939)

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.