RHBA-2013:1630 - Bug Fix Advisory

Topic

Updated systemtap packages that fix several bugs and add various enhancements
are now available for Red Hat Enterprise Linux 6.

Description

SystemTap is a tracing and probing tool to analyze and monitor activities of the
operating system, including the kernel. It provides a wide range of filtering
and analysis options.

The systemtap packages have been upgraded to upstream version 2.3, which
provides a number of bug fixes and enhancements over the previous version.

The most notable enhancements are:

• new support for regular expression matching in script language, using the "=~"

and "!~" operators;

• improved error diagnostics with references to man pages that give further

information and corrective advice;

• new ability to read the perf-counter values in process probes, using the

"@perf()" operator;

• faster stack unwinding functions, especially for partial "unwinds" of only one

or a few call levels;

• new support for a macro processing in the scripting language, using the

"@define" operator;

• various tapset and runtime improvements.

(BZ#920682)

This update also fixes the following bugs:

• Previously, the SystemTap "nfs.proc.commit_done" probe alias interpreted the

underlying arguments incorrectly. As a consequence, incorrect information was
returned. The SystemTap "nfs_proc.commit_done" probe alias has been modified to
interpret the underlying arguments correctly, and it now returns the correct
information. (BZ#920444)

• Prior to this update, the ioblktime.stp example script did not track properly

when I/O block pending requests were merged together with other requests.
Consequently, the associative array could overflow, and an error occurred. The
script has been modified to delete the merged I/O block requests. As a result,
the script no longer fails after array overflow errors. (BZ#743591)

• The stap-serverd daemon did not use the avahi-client API properly. As a

consequence, stap-serverd terminated unexpectedly when the avahi daemon was
stopped or restarted. The underlying source code has been modified to use the
avahi-client API properly, and stap-serverd now handles the described scenario
without crashing. (BZ#874205)

• If the main thread of an application did not go through at least one quiesce,

such as a system call, the SystemTap utility was unable to attach to the
application. Consequently, SystemTap could not detect the events of the
application. SystemTap now interrupts the main application thread so that it can
attach to it. As a result, Systemtap no longer misses any events. (BZ#876848)

• Previously, the SystemTap utility used an arbitrary order when searching for

kernel modules under the /lib/modules/ directory and identified the base module
first. As a consequence, SystemTap could not probe some modules that were
overridden by updates. SystemTap now uses the modules.dep file to order the
module searches so that they match the order of the modprobe program. As a
result, the overridden modules can be probed successfully. (BZ#846789)

• Previously, the SystemTap translator did not always include the correct code

to be able to use the caller() function, which could lead to compile errors.
This update ensures that the SystemTap translator includes the proper runtime
code when using the caller() function. As a result, using caller() no longer
causes compile errors. (BZ#819967)

• Prior to this update, the scope specifiers and IDs for IPv6 addresses were not

handled correctly in SystemTap. Consequently, the user could not connect to
stap-server using IPv6. This update corrects the handling of scope specifiers or
IDs for IPv6 addresses, and the user can now connect to stap-server using IPv6
as expected. (BZ#906061)

• Previously, the "trace" utility in SystemTap generated a low-quality C code.

As a consequence, when the generated code was compiled, the gcc compiler
displayed error messages. This update improves the quality of the generated
code, and no warnings are now displayed as expected. (BZ#902739)

Users of systemtap 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.

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/site/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 x86_64
• 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 i386
• 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 - 819967 - caller() doesn't work in systemtap
• BZ - 902739 - dtrace generates poor quality C code that provokes static analyzers

CVEs

(none)

References

(none)