NAME

       error::pass5 - systemtap pass-5 errors

DESCRIPTION

       Errors that occur during pass 5 (execution) can have a variety of causes.

       exceptional events during script execution
              The systemtap translator and runtime include numerous error checks that aim to protect the systems
              and the users from mistakes or transient conditions.  The script may deliberately call the error()
              tapset  function  to signal a problem.  Some memory needed for accessing $context variables may be
              temporarily unavailable.  Consider using the try/catch  construct  to  wrap  script  fragments  in
              exception-handling code.  Consider using the stap --suppress-handler-errors or stap --skip-badvars
              option.

       resource exhaustion
              One  of  several  types  of space or time resource limits may be exceeded by the script, including
              system overload, too many tuples to be stored in an  array,  etc.   Some  of  the  error  messages
              identify  the constraint by macro name, which may be individually raised.  Consider using the stap
              --suppress-handler-errors and/or  stap  -g  --suppress-time-limits  options.   Extend  or  disable
              individual  resource  limits  using  the  stap  -DSOME_LIMIT=NNNN  option.  The stap -t option may
              identify those probes that are taking too long.

       remote execution server problems
              If you use the stap --remote option to direct a systemtap script to be  executed  somewhere  else,
              ensure  that  an  SSH  connection  may  be  made  to  the remote host, and that it has the current
              systemtap runtime installed & available.

       installation/permission problems
              It is possible that your copy  of  systemtap  was  not  correctly  installed.   For  example,  the
              /usr/bin/staprun  program may lack the necessary setuid permissions, or your invoking userid might
              not have sufficient privileges (root, or stapusr  and  related  group  memberships).   Environment
              variables may interfere with locating /usr/libexec/.../stapio.

       security configuration
              SecureBoot  or  other module signing machinery may be in effect, preventing .ko module loading.  A
              local or remote stap-server service would be necessary to securely manage keys.  This situation is
              detected automatically on most kernels, but on some, the SYSTEMTAP_SIGN  environment  varible  may
              have to be set to trigger this extra signing-related processing.

              The  normal  kernel-module  based  systemtap  backend  may be more than your script requires.  Try
              stap --runtime=bpf and/or stap --runtime=dyninst backends.  Though they have inherent limitations,
              they operate with lesser privileges and perceived risks.

              It may be possible to disable secure/lockdown measures temporarily with the SysRQ+x keystroke,  or
              permanently with sudo mokutil --disable-validation and a reboot.

       errors from target program
              The program invoked by the stap -c CMD option may exit with a non-zero code.

       uncaught exceptions in the target program
              When  using  --runtime=dyninst  you  may encounter an issue where the target program aborts with a
              message like "terminate called after throwing an instance of 'foo_exception'".  This  is  unfortu‐
              nately  a  limitation  of  Dyninst,  which  sometimes  prevents exceptions from properly unwinding
              through instrumented code.

GATHERING MORE INFORMATION

       Increasing the verbosity of pass-5 with an option such as --vp 00001 can help pinpoint the problem.

SEE ALSO

       stap(1),
       http://sourceware.org/systemtap/wiki/TipExhaustedResourceErrors,
       error::fault(7stap),
       error::reporting(7stap)
       warning::pass5(7stap)

                                                                                             ERROR::PASS5(7stap)