NAME¶

error::pass4 - systemtap pass-4 errors

DESCRIPTION¶

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 (git://sourceware.org/git/systemtap.git) 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.

compiler bugs and mysteries

Messages such as "internal compiler error" suggest compiler problems. These should be reported to the compiler developers in the form of a preprocessed .i file, plus the compiler command line. To gather relevant information, run

stap -k --vp 0003 -p4 ....

Systemtap will report the saved temporary directory, and the compiler command line it attempted. Go to the directory to find he main generated file stap_NNNNN_src.c. Force the compiler to produce a preprocessed file with:

make -C /lib/modules/`uname -r`/build M=`pwd` stap_NNNNN_src.i

(note the .i suffix), and the compiler command line should be in the file .stap_NNNNN_src.i.cmd.

SEE ALSO¶

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