error::pass4

Errors that occur during pass 4 (compilation) have generally only a few causes:

kernel or OS version changes

The systemtap runtime and embedded-C fragments in the tapset library are designed to be portable across a wide range of OS versions. However, incompatibilities can occur when some OS changes occur, such as kernel modifications that change functions, types, or macros referenced by systemtap. Upstream builds of systemtap are often quickly updated to include relevant fixes, so try getting or making an updated build. If the issue persists, report the problem to the systemtap developers.

buggy embedded-C code

Embedded-C code in your own guru-mode script cannot be checked by systemtap, and is passed through verbatim to the compiler. Errors in such snippets of code may be found during the pass-4 compiler invocation, though may be hard to identify by the compiler errors.

incompatible embedded-C code

The interface standards between systemtap-generated code and embedded-C code occasionally change. For example, before version 1.8, arguments were passed using macros THIS->foo and THIS->__retvalue but from version 1.8 onward, using STAP_ARG_foo and STAP_RETVALUE. Adjust your embedded-C code to current standards, or use the stap --compatible=VERSION option to make systemtap use a different one.

It may be necessary to run systemtap with -k or -p3 to examine the generated C code. Increasing the verbosity of pass-4 with an option such as --vp 0001 can also help pinpoint the problem.

stap(1), error::reporting(7stap)