Please Install the Updated Packages.

The kernel packages contain the Linux kernel, the core of any Linux operating system. Security fix: * Using the SG_IO IOCTL to issue SCSI requests to partitions or LVM volumes resulted in the requests being passed to the underlying block device. If a privileged user only had access to a single partition or LVM volume, they could use this flaw to bypass those restrictions and gain read and write access (and be able to issue other SCSI commands) to the entire block device. In KVM (Kernel-based Virtual Machine) environments using raw format virtio disks backed by a partition or LVM volume, a privileged guest user could bypass intended restrictions and issue read and write requests (and other SCSI commands) on the host, and possibly access the data of other guests that reside on the same underlying block device. Partition-based and LVM-based storage pools are not used by default. Refer to Red Hat Bugzilla bug 752375 for further details and a mitigation script for users who cannot apply this update immediately. (CVE-2011-4127, Important) Bug fixes: * Previously, idle load balancer kick requests from other CPUs could be serviced without first receiving an inter-processor interrupt (IPI). This could have led to a deadlock. (BZ#750459) * This update fixes a performance regression that may have caused processes (including KVM guests) to hang for a number of seconds. (BZ#751403) * When md_raid1_unplug_device() was called while holding a spinlock, under certain device failure conditions, it was possible for the lock to be requested again, deeper in the call chain, causing a deadlock. Now, md_raid1_unplug_device() is no longer called while holding a spinlock. (BZ#755545) * In hpet_next_event(), an interrupt could have occurred between the read and write of the HPET (High Performance Event Timer) and the value of HPET_COUNTER was then beyond that being written to the comparator (HPET_Tn_CMP). Consequently, the timers were overdue for up to several minutes. Now, a comparison is performed between the value of the counter and the comparator in the HPET code. If the counter is beyond the comparator, the &quot -ETIME&quot error code is returned. (BZ#756426) * Index allocation in the virtio-blk module was based on a monotonically increasing variable &quot index&quot . Consequently, released indexes were not reused and after a period of time, no new were available. Now, virtio-blk uses the ida API to allocate indexes. (BZ#756427) * A bug related to Context Caching existed in the Intel IOMMU support module. ... Description truncated, for more information please check the Reference URL

kernel on CentOS 6

• http://lists.centos.org/pipermail/centos-announce/2011-December/018358.html

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Updated on 2015-03-25