[Octave-bug-tracker] [bug #38616] memory leak in regexprep

[Rik]

Follow-up Comment #5, bug #38616 (project octave):

I started by attempting to reproduce the segfault you describe with this
code.


s="0123456789";
for i=1:21, s=cstrcat(s,s);,endfor

s = regexprep(s,'0','2');
s = regexprep(s,'1','2');
s = regexprep(s,'2','3'); 


Unfortunately this works fine for me with the system I have available for
testing (3.6.4 on x86_64 Linux).

Are you running on a 32-bit or 64-bit architecture?  This would affect the
size of pointers which could be a problem.

Second, the final segfault is replacing 3/10 of the entries in s with a new
value.  3/10 of the size of s is 6291456 or approximately 2^22.6.  So in order
to untangle things, does the following standalone code also cause a segfault?


s = repmat ('2', 1, 2^23);
s = regexprep (s, '2', '3');


Finally, would it be possible for you to compile with debugging and run under
gdb to produce a backtrace?

Something like the following should do it assuming you are using a Bourne sh.


CFLAGS="-g -O0"
CXXFLAGS="-g -O0"
# That is the letter 'O' followed by the numerical digit zero.
export CFLAGS
export CXXFLAGS
./configure --your_options_here
make
# The following runs the newly built octave under gdb
run-octave -g
s="0123456789";
for i=1:21, s=cstrcat(s,s);,endfor

s = regexprep(s,'0','2');
s = regexprep(s,'1','2');
s = regexprep(s,'2','3'); 
# When this produces a segmentation fault, get a backtrace with 'bt'
bt
# And attach the results to this bug report.



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