RHBA-2009:1313 - Bug Fix Advisory

Topic

Updated systemtap packages that fix various bugs, enhance user-space
probing, improve support for debuginfo-less operations and apply several
other enhancements are now available.

Description

SystemTap provides an instrumentation infrastructure for systems running
the Linux 2.6 kernel. It allows users to write scripts that probe and trace
system events for monitoring and profiling purposes. SystemTap's framework
allows users to investigate and monitor a wide variety of wide variety of
kernel functions, system calls, and other evens that occur in both
kernel-space and user-space.

With this update, SystemTap is now re-based on upstream version 0.9.7. This
applies several bug fixes and enhancements, including:

• The systemtap-testsuite package contained test cases that were

incorrectly configured as 'executable' (systemtap.base/bz10078.stp,
buildko/two.stp, and buildok/thirty.stp). Any test runs involving these
cases failed unexpectedly. This release fixes the permissions for all test
cases provided by the systemtap-testsuite package. (BZ#499657)

• On-file flight recording is now supported. This allows stap to run in the

background and record huge trace log information on the disk, rather than
just to memory. (BZ#438737)

• Kernel tracepoints are now supported for probing predefined kernel events

without any debuginfo information. Tracepoints incur less overhead than
kprobes, and context parameters are available with full type information.
For a list of available, supported tracepoints, run the command stap -L
'kernel.trace("*")'. (BZ#475456 and BZ#498040)

• SystemTap log rotation is now supported. With this, a running SystemTap

script can switch to a different log file during on-file flight recording
without stopping. Users can specify a time or log file size that triggers a
log rotation, helping ensure that a SystemTap script never stops recording
information. (BZ#481704)

SystemTap is no longer a technology preview, and now has production
support. Red Hat recommendeds that users run scripts on development
machines before deployment in production environments. Since SystemTap is
an optional diagnostic tool, users can easily stop using it in the event of
a problem. Options such as "-g" for Guru mode, and "-D*", allow users to
disable several security checks. Scripts using these options may not be
supported.

Red Hat plans to fix problems in SystemTap, or the Linux kernel, as they
arise in connection with new scripts. In some cases, a fix may include
extending the blacklist for known areas of the Linux kernel that are unsafe
to probe. All scripts that use probes targeting blacklisted areas will need
to be revised.

This errata contains several other enhancements and bug fixes. For a
complete list of SystemTap updates applied by this errata, please refer to
the SystemTap errata entry in the Red Hat Enterprise Linux 5.4 Technical
Notes available at

http://redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/ Technical_Notes/systemtap.html

SystemTap users are advised to upgrade to this version.

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
http://kbase.redhat.com/faq/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 475456 - [FUJITSU 5.4 FEAT] systemtap tracepoint support
• BZ - 481377 - systemtap rebase for RHEL5.4
• BZ - 485498 - Beginer Guide Install scripts to be included in systemtap rpm
• BZ - 494462 - systemtap sends signals to all processes in process group.
• BZ - 498018 - enable "probe process.insn[.block]" for rhel5-era utrace
• BZ - 498040 - intermittent crashes on prototype kprobe.function("foo") probes for erroneous "foo"
• BZ - 499657 - Bogus testsuite failures due to permissions
• BZ - 499677 - 'Unknown symbol in module' in Pass 5 when probing userspace
• BZ - 499688 - buildok/vfs_testcase.stp fails to build on ppc
• BZ - 501759 - dwfl_offline_section_address: Assertion `mod->e_type == 1' failed.
• BZ - 501795 - sdt.h on powerpc Error: junk at end of line: `0'
• BZ - 504007 - possible intermittent deadlock with uprobes due to task_finder mm_lock holding

CVEs

(none)

References

• http://redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Technical_Notes/systemtap.html