Tcl; Rhba-2009:0414: Bug Fix Update - Red Hat ENTERPRISE LINUX 5.4 - TECHNICAL NOTES Manual

• The systemtap-testsuite package contained test cases (systemtap.base/bz10078.stp,
buildko/two.stp, and buildok/thirty.stp) that were incorrectly configured as "executable".
Any test runs involving these cases failed unexpectedly. This release fixes the permissions for all
test cases provided by the systemtap-testsuite package.
• The context.stp tapset now contains a definition for the task_pt_regs() macro, which is
required to compile some types of SystemTap scripts on the PowerPC platform.
• Compiling any program that used static dynamic trace markers for the STAP_PROBE or
DTRACE_PROBE macros on the PowerPC platform resulted in an error. This was caused by an
incorrect if/else statement in the sdt.h headr file, did not define PowePC as required; as such,
the sdt.h header file supplied an incorrect macro definition for STAP_NOP. With this update, sdt.h
now provides the correct macro definition for STAP_NOP on the PowerPC platform.
• A bug in the implementation of kernel return probe trampolines made it possible for some stack
tracebacks to go undetected. Whenever this occurred, the stack unwinder would not be executed,
resulting in a garbled stack. With this release, the code for detecting the kernel return probe
trampoline is now fixed, ensuring that all stack tracebacks are dealt with accordingly. In addition,
this release also uses the kernel DWARF unwinder automatically in the event of stack tracebacks.
1706
(BZ#503225 )
• A bug in runtime/task_finder.c made it possible for some processes to hold a semaphore
while performing a memory map callback. Whenever this occurred, some tasks would become
deadlocked if they were probed by user-space probes. This update fixes the bug, ensuring that
memory map callbacks are safe and do not cause deadlocks.
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.
SystemTap users are advised to upgrade to this version.

1.220. tcl

1.220.1. RHBA-2009:0414: bug fix update

Note
This update has already been released (prior to the GA of this release) as FASTRACK
RHBA-2009:0414
errata
Updated tcl packages that resolve an issue are now available.
Tcl is a simple scripting language designed to be embedded into other applications. Tcl is designed to
be used with Tk, a widget set.
1708
1703
(BZ#499657 )
(BZ#499688
(BZ#501795
1707
(BZ#504007 )
tcl
1704
)
1705
)
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