RHBA-2015:1391 - Bug Fix Advisory

Topic

Updated device-mapper-multipath packages that fix several bugs and add various
enhancements are now available for Red Hat Enterprise Linux 6.

Description

The device-mapper-multipath packages provide tools that use the device-mapper
multipath kernel module to manage multipath devices.

This update fixes the following bugs:

• If the multipathd daemon failed to add a multipath device, in some

circumstances, it was freeing the alias and then accessing it and attempting to
free it again. Consequently, multipathd terminated unexpectedly. With this
update, multipathd no longer frees the alias twice, or attempts to access the
freed alias, and thus no longer crashes in the described situation. (BZ#880121)

• Previously, any target port with the ALUA preference bit set was given a

higher priority than all other target ports. Consequently, when a target port
had the preference bit set, multipath did not balance load between it and other
ports that were equally optimized. With this update, the preference bit only
increases the priority of paths that are not already optimized. Now, if the
preference bit is set on a non-optimized port, the port is used. However, if the
preference bit is set on an optimized port, all optimized ports are used, and
multipath loads balance across them. (BZ#1120047)

• When the parted utility created partitions on an existing multipath device, it

raced with the kpartx utility to create the partitions. This could cause device
or resource busy errors. Now, kpartx only creates partition devices when the
multipath device is activated, and no longer automatically creates partitions
when parted is run on existing multipath devices. (BZ#1136966)

• Previously, a multipath device was not assigned a user_friendly_name by

initramfs, which caused a conflict with the name already assigned by the normal
system. Because of the name conflict, multipath could try to update the wrong
device, and thus cause data corruption. To fix this bug, multipath checks paths
to see if a device's user_friendly_name is already assigned, and assigns a new
one if it is. (BZ#1148096)

• Previously, the libmultipath utility was keeping a global cache of sysfs data

for all programs, even though this was only necessary for the multipathd daemon.
As a consequence, a memory error could occur when multiple threads were using
libmultipath without locking. This led to unexpected termination of
multithreaded programs using the mpath_persistent_reserve_in() or
mpath_persistent_reserve_out() functions. With this update, only multipathd uses
the global sysfs data cache, and the described crashes are thus avoided.
(BZ#1171862)

• Previously, the first time the multipath utility recognized a path device, the

path device was not claimed in the udev utility, and other programs could race
multipath to claim it. As a consequence, multipath systems could fail to boot
during installation. With this update, the multipathd daemon now checks the
kernel command line on startup. If it has recognized any parameters with a World
Wide Identifier (WWID) value, it adds those WWIDs to the list of multipath
WWIDs. Devices with those WWIDs are thus claimed the first time they are
recognized. As a result, if multipath systems do not boot successfully during
installation, users can add mpath.wwid=[WWID] to the kernel command line to work
around the problem. (BZ#1175888)

In addition, this update adds the following enhancements:

• This update adds new built-in configuration for Dell MD36xxf storage arrays.

(BZ#978947)

• With this udpate, multipath autodetects whether an EMC CLARiiON array is set

up in ALUA or PNR mode, and correctly configures itself to match. (BZ#997028)

• Now, the multipathd daemon has two new configuration options

"delay_watch_checks" and "delay_wait_checks". The user is recommended to refer
to the multipath(8) man page for more information. (BZ#1072081)

Users of device-mapper-multipath are advised to upgrade to these updated
packages, which fix these bugs and add these enhancements.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 880121 - multipathd crash and prevent daemon restart "multipathd: mpathdx: error getting map status string"
• BZ - 1128786 - pg_timeout none results in error messages DM message failed [set_pg_timeout 0]
• BZ - 1171862 - Customer is using libmpathpersist and since updating to device-mapper-multipath-0.4.9-80.el6_6.1 is experiencing application coredumps

CVEs

(none)

References

(none)