The kernel packages contain the Linux kernel, the core of any Linux operating system. This update addresses the following security issues: * the sendmsg function in the Linux kernel did not block during UNIX socket garbage collection. This could, potentially, lead to a local denial of service. * when fput was called to close a socket, the __scm_destroy function in the Linux kernel could make indirect recursive calls to itself. This could, potentially, lead to a local denial of service. * a deficiency was found in the Linux kernel virtual file system implementation. This could allow a local, unprivileged user to make a series of file creations within deleted directories, possibly causing a denial of service. * a buffer underflow flaw was found in the Linux kernel IB700 SBC watchdog timer driver. This deficiency could lead to a possible information leak. By default, the "/dev/watchdog" device is accessible only to the root user. * the hfs and hfsplus file systems code failed to properly handle corrupted data structures. This could, potentially, lead to a local denial of service. * a flaw was found in the hfsplus file system implementation. This could, potentially, lead to a local denial of service when write operations were performed. This update also fixes the following bugs: * when running Red Hat Enterprise Linux 4.6 and 4.7 on some systems running IntelR CPUs, the cpuspeed daemon did not run, preventing the CPU speed from being changed, such as not being reduced to an idle state when not in use. * mmap could be used to gain access to beyond the first megabyte of RAM, due to insufficient checks in the Linux kernel code. Checks have been added to prevent this. * attempting to turn keyboard LEDs on and off rapidly on keyboards with slow keyboard controllers, may have caused key presses to fail. * after migrating a hypervisor guest, the MAC address table was not updated, causing packet loss and preventing network connections to the guest. Now, a gratuitous ARP request is sent after migration. This refreshes the ARP caches, minimizing network downtime. * writing crash dumps with diskdump may have caused a kernel panic on Non-Uniform Memory Access systems with certain memory configurations. * on big-endian systems, such as PowerPC, the getsockopt function incorrectly returned 0 depending on the parameters passed to it when the time to live value equaled 255, possibly causing memory corruption and application crashes. * a problem in the kernel packages provided by the RHSA-2008:0508 advisory caused the Linux kernel"s built-in memory copy procedure to return the wrong error code after recovering from a page fault on AMD64 and Intel 64 systems. This may have caused other Linux kernel functions to return wrong error codes. * a divide-by-zero bug in the Linux kernel process scheduler, which may have caused kernel panics on certain systems, has been resolved. * the netconsole kernel module caused the Linux kernel to hang when slave interfaces of bonded network interfaces were started, resulting in a system hang or kernel panic when restarting the network. * the "/proc/xen/" directory existed even if systems were not running Red Hat Virtualization. This may have caused problems for third-party software that checks virtualization-ability based on the existence of "/proc/xen/". Note: this update will remove the "/proc/xen/" directory on systems not running Red Hat Virtualization. All Red Hat Enterprise Linux 4 users should upgrade to these updated packages, which contain backported patches to resolve these issues.