RHBA-2012:0926 - Bug Fix Advisory

Topic

Updated ltrace packages that fix multiple bugs and add one enhancement are now
available for Red Hat Enterprise Linux 6.

Description

The ltrace utility is a debugging program that runs a specified command until
the command exits. While the command is executing, ltrace intercepts and records
both the dynamic library calls called by the executed process and the signals
received by the executed process. The ltrace utility can also intercept and
print system calls executed by the process.

This update fixes the following bugs:

• Prior to this update, a traced process that had more than one thread could be

aborted if the threads ran into breakpoints which the ltrace utility did not
handle. With this update, ltrace attaches to the newly created threads, and
carefully handles the breakpoints so that tracing events are not missed. This
update also improves the detach logic so that a running process to which ltrace
has been attached is left in a consistent state before detaching. (BZ#742340)

Prior to this update, the ltrace utility could, under certain circumstances,
fail to trace returns from functions which where called with a tail call
optimization. This update adds support for tracing returns from functions called
with a tail call optimization. (BZ#811184)

This update also adds the following enhancement:

• Prior to this update, ltrace could not trace library functions loaded via

libdl. This update changes the behavior of the "-x" option for placing static
breakpoints so that dynamic libraries are also considered and breakpoints set in
them. This works for dynamic libraries that are linked to the binary as well as
those that are opened with the function "dlopen" in runtime. (BZ#738254)

All users of ltrace are advised to upgrade to this updated package, which fixes
these bugs and adds this update.

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 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 - 742340 - ltrace cannot properly handle multi-threaded processes

CVEs

(none)

References

(none)