RHBA-2015:0404 - Bug Fix Advisory

Topic

Updated gdb packages that fix several bugs and add various enhancements are now
available for Red Hat Enterprise Linux 7.

Description

The gdb packages provide the GNU Debugger (GDB) to debug programs written in C,
C++, Java, and other languages by executing them in a controlled fashion and
then printing out their data.

This update fixes the following bugs:

• Previously, GDB did not correctly handle shared objects that contained

identical exported global variables. Consequently, when the user tried to
inspect the global variable exported by such shared objects, GDB displayed an
incorrect value. This bug has been fixed, and GDB now correctly handles
different shared objects that export the same global variable. (BZ#809179)

• On files generated by dwz (DWARF Compressor), GDB was ineffectively handling

DW_TAG_partial_unit compilation units that contained DW_AT_stmt_list attribute
(line number information) of the same value by fully decoding the same
.debug_line unit in each DW_TAG_partial_unit. As a consequence, the user noticed
significant delays when asking for certain GDB operations on files processed by
dwz. For example, when requesting a full backtrace of a large multi-threaded
program. With this update, GDB caches parsed .debug_line units and reuses that
information for the remaining DW_TAG_partial_unit compilation units, using the
same DW_AT_stmt_list values. Additionally, GDB now parses only a part of the
.debug_line unit if it is required only for DW_TAG_partial_unit. As a result,
the delays no longer occur in this scenario, and GDB performance can be up to
100 times higher under certain circumstances. (BZ#1103894)

• The gdb-add-index script did not correctly handle paths to binary files

located in the current working directory. Consequently, the user could not
specify a binary file without using its full or relative path. With this update,
gdb-add-index has been fixed to correctly handle binary files in the current
working directory when no path is specified. (BZ#1104029)

• Previously, GDB was unable to correctly access Thread Local Storage (TLS) data

on statically linked binary files. Consequently, the user could not inspect TLS
data on the program being debugged if the program was linked statically. This
bug has been fixed, and users can now inspect TLS data on statically linked
binary files as expected. (BZ#1080657)

• Prior to this update, GDB used the __errno_location() function call to

retrieve the errno value for both non-threaded and threaded programs.
Consequently, an attempt to display the errno variable from a core file failed
because no function calls are possible when analyzing core files. A patch has
been applied, and GDB now uses __errno_location() only for live processes (not
core files) and correctly displays the errno values for both non-threaded and
threaded programs. (BZ#1166549)

In addition, this update adds the following enhancements:

• Support for the ARM 64-bit architecture, which extends the ARM architecture by

allowing 64-bit instruction-set, has been added to GDB. (BZ#1027479)

• Support for the little-endian variant of IBM POWER systems has been

implemented in this update of GDB. (BZ#1125820)

• Previously, it was inconvenient to append new directories using the "set

auto-load scripts-directory" command. Consequently, using the "set auto-load
scripts-directory" command rewrote the original value, and previous
configuration was lost. This update has introduced the
"add-auto-load-scripts-directory" command, which appends specified directories
to an existing "set/show auto-load scripts-directory" value instead of replacing
it, and the entries in the former directory list are preserved. (BZ#1163339)

Users of gdb 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 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 809179 - Global variable nested by another dso shows up incorrectly in gdb
• BZ - 1080657 - [RHEL7] Can't access TLS variables in statically linked binaries
• BZ - 1104029 - gdb-add-index has problem parsing arguments
• BZ - 1163339 - [RFE] please add add-auto-load-scripts-directory command

CVEs

(none)

References

(none)