[Bug 3625] New: [SystemTap 3.2] arc_priority representation creates an implicit limit on character sequence within regexp

[bugzilla-daemon at icedtea.classpath.org]

https://icedtea.classpath.org/bugzilla/show_bug.cgi?id=3625

            Bug ID: 3625
           Summary: [SystemTap 3.2] arc_priority representation creates an
                    implicit limit on character sequence within regexp
           Product: IcedTea
           Version: 3.x-hg
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P5
         Component: SystemTap
          Assignee: mark at klomp.org
          Reporter: sgehwolf at redhat.com
                CC: unassigned at icedtea.classpath.org

SystemTap 3.2 contains changes to the regexp code which results in an implicit
limit on the length of a regexp. If the regexp is too long an assertion will be
thrown. Example:

stap: stapregex-dfa.cxx:152: stapregex::arc_priority
stapregex::refine_lower(const arc_priority&): Assertion `a.first <=
(9223372036854775807LL * 2ULL + 1)/4' failed. 

This code was originally discovered by downstream RHEL OpenJDK 8 packages where
this:
http://icedtea.classpath.org/hg/icedtea8/file/17f5a2d00f97/tapset/jstack.stp.in#l51

expands to:

[...]
%( systemtap_v >= "3.0" %? if (pp() !~
"/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.181-3.b13.el7_5.x86_64/") next %)
[...]

Since "/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.181-3.b13.el7_5.x86_64/" exceeds a
certain length, the bug is being triggered. One proposed work-around was to
change this to:

@define _check_match %(
  %( systemtap_v >= "3.2" %? if (strpos(pp(),"@prefix@") < 0) next %)
%)

We should consider implementing this work-around.

See:
https://bugzilla.redhat.com/show_bug.cgi?id=1623579

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