[Octave-bug-tracker] [bug #51589] crash on regexp

[Mike Miller]

Follow-up Comment #5, bug #51589 (project octave):

Dan - the segmentation fault looks to me to be due to excessively large number
of stack frames, i.e. overflow due to recursion.

On my system, my example first errors out around a length of 7923. I say
around because it is not deterministic, at 7925 it crashes 100% of the time,
at 7923 it crashes maybe 20% of the time.

If I then decrease the maximum stack size soft limit (ulimit -s), it crashes
at a much smaller subject string size. It's about proportional, decrease the
stack size limit by half, the subject string crash limit also halves.

So this goes back to the PCRE implementation which uses stack recursion in
some way to deal with match groups, and the library has internal variables to
set limits on the number of matches and the maximum recursion limit, but I
haven't fully looked into what these tunable parameters do. These things are
referred to in the PCRE docs, so I wouldn't jump to calling it a bug, but a
tunable parameter that might need to be adjusted in how Octave uses PCRE.

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?51589>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/