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
              unfortunately 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)