RHBA-2014:0375 - Bug Fix Advisory

Topic

Updated libvirt packages that fix several bugs are now available for Red Hat
Enterprise Linux 6.

Description

The libvirt library is a C API for managing and interacting with the
virtualization capabilities of Linux and other operating systems. In addition,
libvirt provides tools for remote management of virtualized systems.

This update fixes the following bugs:

• When hot unplugging a virtual CPU (vCPU) from a guest, the current Red Hat

Enterprise Linux QEMU implementation does not remove the corresponding vCPU
thread. Because of this, libvirt previously did not correctly perceive the vCPU
count after a vCPU had been hot unplugged. Consequently, an error occured in
libvirt, which prevented increasing in the vCPU count after the hot unplug. In
this update, information from QEMU is used to filter out inactive vCPU threads
of disabled vCPUs, and the internal checks now pass and allow the hot plug.
(BZ#1080439)

• Prior to this update, there was a typographical error in a condition that

checks whether QEMU successfully attached a new disk to a guest. Due to the
error, the libvirtd daemon terminated unexpectedly if the monitor command was
unsuccesful; for instance, in case of a virtual machine failure or when
attaching a guest disk drive was interrupted. In this update, the error has been
corrected, and libvirtd no longer crashes in the described circumstances.
(BZ#1080471)

• A previous update introduced an error where a SIG_SETMASK argument was

incorrectly replaced by a SIG_BLOCK argument after the poll() system call.
Consequently, the SIGCHLD signal could be permanently blocked, which caused
signal masks not to return to their original values and defunct processes to be
generated. With this update, the original signal masks are restored as intended,
and poll() now functions correctly. (BZ#1080501)

Users of libvirt are advised to upgrade to these updated packages, which fix
these bugs. After installing the updated packages, libvirtd will be restarted
automatically.

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

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Server - AUS 6.5 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 IBM z Systems - Extended Update Support 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 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 6 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1080471 - libvirtd crashes if VM crashes or is destroyed while hot-attaching disks
• BZ - 1080501 - use of tls with libvirt.so can leave zombie processes

CVEs

(none)

References

(none)