Issued:

2017-11-30

Updated:

2017-11-30

RHBA-2017:3296 - glibc bug fix update

Synopsis

glibc bug fix update

Type/Severity

Bug Fix Advisory None

Topic

Updated glibc packages that fix several bugs are now available for Red Hat Enterprise Linux 7.

Description

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

This update fixes the following bugs:

• Previously, the dynamic loader in the GNU C library (glibc) contained an optimization which avoided saving and restoring vector registers for 64-bit Intel and AMD architectures. Consequently, applications compiled for these architectures and using unsupported vector registers for passing function arguments, not adhering to the published x86-64 psABI specification, could fail and produce unexpected results. This update changes the dynamic loader to use the XSAVE/XSAVEC context switch CPU instructions, preserving more CPU state, including all vector registers. As a result, applications using vector registers for argument passing, in ways which are not supported by the x86-64 psABI specification, work as expected. (BZ#1513070)

• Previous versions of the GNU C library (glibc) provided a hardware capability check to detect enabled hardware transactional memory (HTM) for 64-bit IBM POWER8 and POWER9 systems. This check did not include the capability to distinguish whether HTM could be suspended or not. This update enhances the hardware capabilities header with PPC_FEATURE2_HTM_NO_SUSPEND to allow applications to test for this bit in AT_HWCAP2 from the getauxval() function and determine if HTM supports suspend or not. (BZ#1515114)

• Previously, the memcpy() routine from the glibc library used unaligned vector loads and stores on 64-bit IBM POWER9 systems. Consequently, the performance of memcpy() over all types of memory accesses was not optimal. The memcpy() routine has been enhanced to provide better performance for applications regardless of the memory involved in the copy. This performance improvement includes POWER7 processors and later, including POWER9. (BZ#1516402)

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.

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

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

Affected Products

Updated Packages

• glibc-devel-2.17-196.el7_4.2.ppc64le.rpm
• glibc-devel-2.17-196.el7_4.2.ppc.rpm
• glibc-2.17-196.el7_4.2.src.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.ppc64.rpm
• glibc-2.17-196.el7_4.2.ppc64.rpm
• glibc-utils-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.ppc64le.rpm
• glibc-utils-2.17-196.el7_4.2.x86_64.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.x86_64.rpm
• glibc-utils-2.17-196.el7_4.2.ppc64le.rpm
• glibc-devel-2.17-196.el7_4.2.s390x.rpm
• glibc-common-2.17-196.el7_4.2.ppc64.rpm
• glibc-debuginfo-2.17-196.el7_4.2.x86_64.rpm
• glibc-2.17-196.el7_4.2.s390x.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.s390x.rpm
• glibc-headers-2.17-196.el7_4.2.ppc64le.rpm
• glibc-static-2.17-196.el7_4.2.s390.rpm
• glibc-static-2.17-196.el7_4.2.s390x.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.s390.rpm
• glibc-common-2.17-196.el7_4.2.ppc64le.rpm
• glibc-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-2.17-196.el7_4.2.i686.rpm
• glibc-debuginfo-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-2.17-196.el7_4.2.ppc64.rpm
• glibc-headers-2.17-196.el7_4.2.ppc64.rpm
• glibc-headers-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-2.17-196.el7_4.2.ppc.rpm
• glibc-static-2.17-196.el7_4.2.ppc64.rpm
• glibc-common-2.17-196.el7_4.2.x86_64.rpm
• glibc-static-2.17-196.el7_4.2.i686.rpm
• glibc-debuginfo-2.17-196.el7_4.2.s390.rpm
• nscd-2.17-196.el7_4.2.ppc64.rpm
• glibc-utils-2.17-196.el7_4.2.ppc64.rpm
• nscd-2.17-196.el7_4.2.ppc64le.rpm
• glibc-debuginfo-2.17-196.el7_4.2.ppc64le.rpm
• glibc-utils-2.17-196.el7_4.2.s390x.rpm
• glibc-devel-2.17-196.el7_4.2.s390.rpm
• glibc-static-2.17-196.el7_4.2.x86_64.rpm
• glibc-2.17-196.el7_4.2.s390.rpm
• glibc-devel-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.i686.rpm
• glibc-2.17-196.el7_4.2.i686.rpm
• nscd-2.17-196.el7_4.2.aarch64.rpm
• nscd-2.17-196.el7_4.2.s390x.rpm
• glibc-devel-2.17-196.el7_4.2.i686.rpm
• glibc-headers-2.17-196.el7_4.2.s390x.rpm
• nscd-2.17-196.el7_4.2.x86_64.rpm
• glibc-static-2.17-196.el7_4.2.ppc.rpm
• glibc-2.17-196.el7_4.2.ppc64le.rpm
• glibc-debuginfo-common-2.17-196.el7_4.2.ppc.rpm
• glibc-static-2.17-196.el7_4.2.ppc64le.rpm
• glibc-devel-2.17-196.el7_4.2.x86_64.rpm
• glibc-headers-2.17-196.el7_4.2.x86_64.rpm
• glibc-2.17-196.el7_4.2.ppc.rpm
• glibc-common-2.17-196.el7_4.2.aarch64.rpm
• glibc-debuginfo-2.17-196.el7_4.2.s390x.rpm
• glibc-common-2.17-196.el7_4.2.s390x.rpm
• glibc-2.17-196.el7_4.2.x86_64.rpm
• glibc-devel-2.17-196.el7_4.2.ppc64.rpm
• glibc-static-2.17-196.el7_4.2.aarch64.rpm

Fixes

(none)

CVEs

(none)

References

(none)

Additional information

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