ERROR::PASS2(7stap)					   ERROR::PASS2(7stap)

NAME
       error::pass2 - systemtap pass-2 errors

DESCRIPTION
       Errors  that  occur  during  pass 2 (elaboration) can have a variety of
       causes.	Common types include:

       unavailable probe point classes
	      Some types of probe points are only available on certain	system
	      versions, architectures, and configurations.  For example, user-
	      space process.*  probes may require utrace or uprobes capability
	      in the kernel for this architecture.

       unavailable probe points
	      Some  probe  points  may	be  individually unavailable even when
	      their class is fine.  For example, kprobe.function("foobar") may
	      fail  if	function foobar does not exist in the kernel any more.
	      Debugging or symbol data may be absent for some types of	.func‐
	      tion  or .statement probes; check for availability of debuginfo.
	      Use  a  wildcard	parameter  such	 as  stap   -l	 'kprobe.func‐
	      tion("*foo*")'  to  locate  still-existing variants.  Use ! or ?
	      probe point suffixes to  denote  optional	 /  preferred-alterna‐
	      tives, to let the working parts of a script continue.

       typos  There  might  be a spelling error in the probe point name ("syc‐
	      sall" vs.	 "syscall").  Wildcard probes may not find a match  at
	      all in the tapsets.  Recheck the names using stap -l PROBEPOINT.
	      Another common mistake is to use the .  operator instead of  the
	      correct  ->  when	 dereferencing	context	 variable subfields or
	      pointers:	 $foo->bar->baz	 even  if   in	 C   one   would   say
	      foo->bar.baz.

       unavailable context variables
	      Systemtap scripts often wish to refer to variables from the con‐
	      text of the probed programs  using  $variable  notation.	 These
	      variables	 may not always be available, depending on versions of
	      the compiler, debugging/optimization flags  used,	 architecture,
	      etc.  Use stap -L PROBEPOINT to list available context variables
	      for given probes.	 Use the @defined() expression to test for the
	      resolvability  of a context variable expression.	Consider using
	      the stap --skip-badvars option to silently  replace  misbehaving
	      context variable expressions with zero.

GATHERING MORE INFORMATION
       Increasing  the	verbosity of pass-2 with an option such as --vp 02 can
       help pinpoint the problem.

SEE ALSO
       stap(1),	  stapprobes(3stap),   probe::*(3stap),	  error::dwarf(7stap),
       error::inode-uprobes(7stap),  warning::debuginfo(7stap), error::report‐
       ing(7stap)

							   ERROR::PASS2(7stap)

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