RHBA-2013:0423 - Bug Fix Advisory

Topic

Updated trace-cmd packages that fix two bugs and add one enhancement are now
available for Red Hat Enterprise Linux 6.

Description

The trace-cmd packages contain a command-line tool that interfaces with the
ftrace utility in the kernel.

This update fixes the following bugs:

• The trace-cmd extract command read a buffer multiple times even after an EOF

condition. Consequently, the output of the trace-cmd command contained duplicate
data. With this update, the trace-cmd utility has been modified to respect the
EOF condition and avoid duplication of data in its output. (BZ#746656)

• When using the latency tracer, the start_threads() function was not called.

Calling the stop_threads() function without first calling start_threads() caused
the trace-cmd record command to terminate with a segmentation fault because PIDs
were not initialized. Consequently, the trace.dat file was not generated. With
this update, stop_threads() is not called unless start_threads() is called
first. As a result, the segmentation fault no longer occurs. (BZ#879792)

In addition, this update adds the following enhancement:

• Previously, the trace-cmd record command was able to filter ftrace data based

on a single PID only. With this update, multiple PIDs can be specified by using
the "-P" option. (BZ#838746)

Users of trace-cmd are advised to upgrade to these updated packages, which fix
these bugs and add this enhancement.

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 x86_64
• 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 (for IBM z Systems) 6 s390x

Fixes

• BZ - 838746 - support multiple pids in set_pid_ftrace

CVEs

(none)

References

(none)