RHBA-2013:1169 - Bug Fix Advisory

Topic

Updated kernel packages that fix several bugs are now available for Red Hat
Enterprise Linux 6 Extended Update Support.

Description

The kernel packages contain the Linux kernel, which is the core of any Linux
operating system.

This update fixes the following bugs:

• A race condition between the read_swap_cache_async() and get_swap_page()

functions in the Memory management (mm) code could lead to a deadlock situation.
The deadlock could occur only on systems that deployed swap partitions on
devices supporting block DISCARD and TRIM operations if kernel preemption was
disabled (the !CONFIG_PREEMPT parameter). If the read_swap_cache_async()
function was given a SWAP_HAS_CACHE entry that did not have a page in the swap
cache yet, a DISCARD operation was performed in the scan_swap_map() function.
Consequently, completion of an I/O operation was scheduled on the same CPU's
working queue the read_swap_cache_async() was running on. This caused the thread
in read_swap_cache_async() to loop indefinitely around its "-EEXIST" case,
rendering the system unresponsive. The problem has been fixed by adding an
explicit cond_resched() call to read_swap_cache_async(), which allows other
tasks to run on the affected CPU, and thus avoiding the deadlock. (BZ#977666)

• The bnx2x driver could have previously reported an occasional MDC/MDIO timeout

error along with the loss of the link connection. This could happen in
environments using an older boot code because the MDIO clock was set in the
beginning of each boot code sequence instead of per CL45 command. To avoid this
problem, the bnx2x driver now sets the MDIO clock per CL45 command.
Additionally, the MDIO clock is now implemented per EMAC register instead of per
port number, which prevents ports from using different EMAC addresses for
different PHY accesses. Also, boot code or Management Firmware (MFW) upgrade is
required to prevent the boot code (firmware) from taking over link ownership if
the driver's pulse is delayed. The BCM57711 card requires boot code version
6.2.24 or later, and the BCM57712/578xx cards require MFW version 7.4.22 or
later. (BZ#982113)

• If the audit queue is too long, the kernel schedules the kauditd daemon to

alleviate the load on the audit queue. Previously, if the current audit process
had any pending signals in such a situation, it entered a busy-wait loop for the
duration of an audit backlog timeout because the wait_for_auditd() function was
called as an interruptible task. This could lead to system lockup in
non-preemptive uniprocessor systems. This update fixes the problem by setting
wait_for_auditd() as uninterruptible. (BZ#982467)

• The kernel could rarely terminate instead of creating a dump file when a

multi-threaded process using FPU aborted. This happened because the kernel did
not wait until all threads became inactive and attempted to dump the FPU state
of active threads into memory which triggered a BUG_ON() routine. A patch
addressing this problem has been applied and the kernel now waits for the
threads to become inactive before dumping their FPU state into memory.
(BZ#988225)

• Due to hardware limits, the be2net adapter cannot handle packets with size

greater than 64 KB including the Ethernet header. Therefore, if the be2net
adapter received xmit requests exceeding this size, it was unable to process the
requests, produced error messages and could become unresponsive. To prevent
these problems, GSO (Generic Segmentation Offload) maximum size has been reduced
to account for the Ethernet header. (BZ#990080)

• BE family hardware could falsely indicate an unrecoverable error (UE) on

certain platforms and stop further access to be2net-based network interface
cards (NICs). A patch has been applied to disable the code that stops further
access to hardware for BE family network interface cards (NICs). For a real UE,
it is not necessary as the corresponding hardware block is not accessible in
this situation. (BZ#990085)

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.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/site/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 i386
• Red Hat Enterprise Linux Server - AUS 6.2 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.2 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.2 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 i386
• Red Hat Storage 2.0 x86_64
• Red Hat Gluster Storage Server for On-premise 2.0 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.0 x86_64

Fixes

CVEs

(none)

References

(none)