1.171.2. RHBA-2011:1044: systemtap bug fix update

Updated systemtap packages that fix several bugs are now available for Red Hat Enterprise Linux 5.

SystemTap is an instrumentation system for systems running the Linux kernel. The system allows developers to write scripts to collect data on the operation of the system.

This update fixes the following bugs:

* Previously, the buildok/fortyfive.stp test case failed to build with SystemTap on the Itanium systems. The problem has been fixed in this update. (BZ#559599)

* Previously, the systemtap service was not stopped and restarted after the "service systemtap stop" and "service systemtap restart" commands were issued. Instead, the service only stopped and was not restarted. This update fixes the problem so that the systemtap service now behaves as expected. (BZ#607232)

* Previously, there was a timing issue when running the "service systemtap restart" command in that a test case for the systemtap-initscript package sometimes failed to restart the service when a script was running. This issue has been resolved with this update so that the command runs correctly now. (BZ#644350)

* After prelink had been run on a system based on the i686 platform, using SystemTap user-space probes that targeted functions or statements in certain shared libraries, or executables based on a separate debuginfo file, caused resolution to the wrong PC location in a linked binary. As a result, the intended probes failed to fire at the correct place in the program, which could have caused the program to crash or misbehave due to a corrupted instruction sequence resulting from incorrect breakpoint insertions. With this update, the libdwfl library code (the libdw.so shared object library) was adjusted to use a more reliable method of compensating for prelink's effect on the address layout of a binary when aligning a runtime PC address with an address computed separately from the separated debuginfo file. SystemTap probes should now work the same on prelinked binaries as they would on binaries that have not been prelinked. (BZ#646870)

* On the i386 platform, there was a semantic error found in the buildok/scheduler-ctxswitch.stp test case, which limited SystemTap's testsuite and tapset portability. This update fixes the problem. (BZ#661424)

* Previously, an itrace (process("PROC").insn) probe could have resulted in a kernel panic as a result of an incorrect PID being used when setting up the probe. The problem has been fixed in this update so that the probe no longer results in a kernel panic. (BZ#699342)

All users requiring SystemTap are advised to upgrade to these updates packages, which fix these bugs.