RHBA-2011:1699 - Bug Fix Advisory

Topic

Updated gdb packages that fix multiple bugs and add three enhancements are now
available for Red Hat Enterprise Linux 6.

Description

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

This update provides fixes for the following bugs:

• Prior to this update, GDB could stop on error when trying to access the

libpthread shared library before the library was relocated. Fixed GDB lets the
relocations to be resolved first, making such program debuggable. (BZ#669432)

• The Intel Fortran Compiler records certain debug info symbols in uppercase but

the gfortran compiler writes case-insensitive symbols in lowercase. As a result,
GDB could terminate unexpectedly when accessing uppercase characters in the
debug information from the Intel Fortran Compiler. With this update, GDB
properly implements case insensitivity and ignores the symbols case in the
symbol files. (BZ#669434)

• When the user selected the "-statistics" option with a negative number as a

result, GDB printed the minus sign twice. This has been fixed and GDB now
displays negative numbers with one minus sign only. (BZ#692386)

• On the PowerPC and the IBM System z architectures, GDB displayed only LWP

(light-weight process) identifiers which matched the Linux TID (Thread
Identifier) values for the threads found in the core file. GDB has been fixed to
initialize the libthread_db threads debugging library when accessing the core
file. GDB now correctly displays the pthread_t identifier in addition to the LWP
identifier on the aforementioned architectures. (BZ#697900)

• Structure field offsets above 65535 described by the DWARF

DW_AT_data_member_location attribute were improperly interpreted as a 0 value.
GDB has been modified and can now handle also large structures and their fields.
(BZ#702427)

• The difference between the very closely related "ptype" and "whatis" commands

was not clearly defined in the gdb info manual. Detailed differences between
these commands have been described in the manual. (BZ#704010)

• Prior to this update, the "info sources" subcommand printed only relative

paths to the source files. GDB has been modified to correctly display the full
path name to the source file. (BZ#712117)

• Modifying a string in the executable using the "-write" command line option

could fail with an error if the executable was not running. With this update,
GDB can modify executables even before they are started. (BZ#730475)

This update also adds the following enhancements:

• With this update, Float16 instructions on future Intel processors are now

supported. (BZ#696890)

• Debugged programs can open many shared libraries on demand at runtime using

the dlopen() function. Prior to this update, tracking shared libraries that were
in use by the debugged program could lead to overhead. The debugging performance
of GDB has been improved: the overhead is now lower if applications load many
objects. (BZ#698001)

• Prior to this update, GDB did not handle DWARF 4 .debug_types data correctly.

Now, GDB can correctly process data in the DWARF 4 format. (BZ#718141)

All GDB users are advised to upgrade to these updated gdb packages, which fix
these bugs and add these enhancements.

Solution

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

This update is available via Red Hat Network. Details on how to use the Red Hat
Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

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 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 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• 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 - 669434 - internal-error: print_frame_args: Assertion `nsym != NULL' failed
• BZ - 692386 - [6.1] '-statistics' option of gdb outputs '-' twice.
• BZ - 697900 - gdb: Linux core files should use linux-thread-db.c also on ppc and s390x
• BZ - 702427 - gdb cannot "handle" a large data structure
• BZ - 704010 - make gdb's help a bit clearer re: ptype & whatis

CVEs

(none)

References

(none)