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B.38.7. RHBA-2012:0540 — kernel bug fix update

Updated kernel packages that fix one bug and add one enhancement are now available for Red Hat Enterprise Linux 6 Extended Update Support.
[Updated 12 June 2012] This advisory has been updated with the correct description for bug 811297. The packages included in this revised update have not been changed in any way from the packages included in the original advisory.
The kernel packages contain the Linux kernel, the core of any Linux operating system.
Bug Fix
Due to incorrect use of the list_for_each_entry_safe() macro, the enumeration of remote procedure calls (RPCs) priority wait queue tasks stored in the tk_wait.links list failed. As a consequence, the rpc_wake_up() and rpc_wake_up_status() functions failed to wake up all tasks. This caused the system to become unresponsive and could significantly decrease system performance. Now, the list_for_each_entry_safe() macro is no longer used in rpc_wake_up(), ensuring reasonable system performance.
The Intelligent Platform Management Interface (IPMI) specification requires a minimum communication timeout of five seconds. Previously, the kernel incorrectly used a timeout of 1 second. This could result in failures to communicate with Baseboard Management Controllers (BMC) under certain circumstances. With this update, the timeout has been increased to five seconds to prevent such problems.
All users of kernel are advised to upgrade to these updated packages, which fix this bug and add this enhancement. The system must be rebooted for this update to take effect.