RHBA-2013:1046 - Bug Fix Advisory

Topic

Updated glibc packages that fix two bugs are now available for Red Hat
Enterprise Linux 6.

Description

The glibc packages provide the standard C and standard math libraries used by
multiple programs on the system. Without these libraries, the Linux system
cannot function correctly.

This update fixes the following bugs:

• A fix to prevent logic errors in various mathematical functions, including

exp, exp2, expf, exp2f, pow, sin, tan, and rint, caused by inconsistent results
when the functions were used with the non-default rounding mode, creates
performance regressions for certain inputs. The performance regressions have
been analyzed and the core routines have been optimized to bring performance
back to reasonable levels. (BZ#964044)

• A program that opens and uses dynamic libraries which use thread-local storage

variables may terminate unexpectedly with a segmentation fault when it is being
audited by a module that also uses thread-local storage. This update modifies
the dynamic linker to detect such a condition, and crashes no longer occur in
the described scenario. (BZ#970992)

Users of glibc are advised to upgrade to these updated packages, which fix these
bugs.

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/knowledge/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 6.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.4 i386
• Red Hat Enterprise Linux Server - AUS 6.4 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 6.4 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.4 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 Update Support from RHUI 6.4 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 i386
• Red Hat Gluster Storage Server for On-premise 2.1 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 964044 - serious CPU time regressions in the glibc math library
• BZ - 970992 - [PATCH] Correctly determine when the application required DSOs with TLS and bump the generation counter

CVEs

(none)

References

(none)