The kernel packages contain the Linux kernel, the core of any Linux operating system. This update fixes the following security issues: * Flaws in the AGPGART driver implementation when handling certain IOCTL commands could allow a local user to cause a denial of service or escalate their privileges. * An integer overflow flaw in agp_allocate_memory could allow a local user to cause a denial of service or escalate their privileges. * A race condition flaw was found in the Linux kernel"s eCryptfs implementation. A local attacker could use the mount.ecryptfs_private utility to mount a directory they would otherwise not have access to. Note: To correct this issue, the RHSA-2011:1241 ecryptfs-utils update, which provides the user-space part of the fix, must also be installed. * A denial of service flaw was found in the way the taskstats subsystem handled the registration of process exit handlers. A local, unprivileged user could register an unlimited amount of these handlers, leading to excessive CPU time and memory use. * A flaw was found in the way mapping expansions were handled. A local, unprivileged user could use this flaw to cause a wrapping condition, triggering a denial of service. * A flaw was found in the Linux kernel"s Performance Events implementation. It could falsely lead the NMI Watchdog to detect a lockup and panic the system. A local, unprivileged user could use this flaw to cause a denial of service using the perf tool. * A flaw in skb_gro_header_slow in the Linux kernel could lead to GRO fields being left in an inconsistent state. An attacker on the local network could use this flaw to trigger a denial of service. GRO is enabled by default in all network drivers that support it. * A flaw was found in the way the Linux kernel"s Performance Events implementation handled PERF_COUNT_SW_CPU_CLOCK counter overflow. A local, unprivileged user could use this flaw to cause a denial of service. * A flaw was found in the Linux kernel"s Trusted Platform Module implementation. A local, unprivileged user could use this flaw to leak information to user-space. * Flaws were found in the tpacket_rcv and packet_recvmsg functions in the Linux kernel. A local, unprivileged user could use these flaws to leak information to user-space. Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting CVE-2011-1745, CVE-2011-2022, CVE-2011-1746, and CVE-2011-2484; the Ubuntu Security Team for reporting CVE-2011-1833; Robert Swiecki for reporting CVE-2011-2496; Li Yu for reporting CVE-2011-2521; Brent Meshier for reporting CVE-2011-2723; and Peter Huewe for reporting CVE-2011-1160. The Ubuntu Security Team acknowledges Vasiliy Kulikov of Openwall and Dan Rosenberg as the original reporters of CVE-2011-1833. This update also fixes various bugs and adds one enhancement. Documentation for these changes will be available shortly from the Technical Notes document linked to in the References section. Users should upgrade to these updated packages, which contain backported patches to correct these issues, and fix the bugs and add the enhancement noted in the Technical Notes. The system must be rebooted for this update to take effect.