2.42. systemtap

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.
  • The systemap-testsuite subpackage is designed for installation on development Workstation machines, not limited Client variants. More complete RPM dependencies now mandate the presence of several non-Client RPM packages, so it is no longer installable on the Client variant. Attempting to update can fail if the update includes the system-testsuite subpackage. To work around this problem remove the systemtap-testsuite subpackage from a Client machine before upgrading the systemtap package.
  • Running some user-space probe test cases provided by the systemtap-testsuite package fail with an Unknown symbol in module error on some architectures. These test cases include (but are not limited to):
    • systemtap.base/uprobes.exp
    • systemtap.base/bz10078.exp
    • systemtap.base/bz6850.exp
    • systemtap.base/bz5274.exp
    Because of a known bug in the latest SystemTap update, new SystemTap installations do not unload old versions of the uprobes.ko module. Some updated user-space probe tests provided by the systemtap-testsuite package use symbols available only in the latest uprobes.ko module (also provided by the latest SystemTap update). As such, running these user-space probe tests result in the error mentioned earlier.
    If you encounter this error, simply run rmmod uprobes to manually remove the older uprobes.ko module before running the user-space probe test again. (BZ#499677)
  • SystemTap currently uses GCC to probe user-space events. GCC is, however, unable to provide debuggers with precise location list information for parameters. In some cases, GCC also fails to provide visibility on some parameters. As a consequence, SystemTap scripts that probe user-space may return inaccurate readings. (BZ#239065)