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Hello,
I'm using perl library GD-2.23 and system library gd-2.0.32.
The following piece of perl code crashes the library. But only when part of a larger program. It works fine when run as stand-alone program...
===============================
<snip>
my $graph;
$graph = GD::Graph::lines->new(800, 600);
$graph->set(
x_label => 'Month',
y_label => 'Amount',
zero_axis => 1,
title => 'Groups for each month (Amounts)',
line_width => 2,
x_labels_vertical => 1,
legend_placement => 'BC'
);
$graph->set_legend(@legend_keys);
my $gd = $graph->plot(\@dataAbsolute);
my $file = WebGUI::Attachment->new("graphAbsolute",$thisWobjectId);
open(IMG, ">/tmp/graphAbsolute_$thisWobjectId.png");
binmode IMG;
print IMG $gd->png();
#print IMG "Hoi";
IMG->close();
<snip>
===============================
I traced it down to the following stack:
===============================
#0 0xb7eb5182 in pthread_mutex_lock () from /lib/libpthread.so.0
#1 0xb7d78ced in free () from /lib/libc.so.6
#2 0xb6bdbfce in gdFree () from /usr/lib/libgd.so.2
#3 0x09bea30c in ?? ()
#4 0x098d63d8 in ?? ()
#5 0xb6de479c in ?? () from /usr/lib/perl5/vendor_perl/5.8.6/i686-linux/auto/GD/GD.so
#6 0xb6dd57b7 in XS_GD__Image_png () from /usr/lib/perl5/vendor_perl/5.8.6/i686-linux/auto/GD/GD.s
+o
#7 0x0827b548 in ?? ()
#8 0xb791b424 in PL_utf8_tolower () from /usr/lib/libperl.so.1
#9 0x00001e04 in ?? ()
#10 0xb791199c in ?? () from /usr/lib/libperl.so.1
#11 0x098d9dc8 in ?? ()
===============================
And:
===============================
#0 0xb7d3f0b1 in kill () from /lib/libc.so.6
#1 0xb7eb71e1 in pthread_kill () from /lib/libpthread.so.0
#2 0xb7eb755b in raise () from /lib/libpthread.so.0
#3 0xb7d3ee44 in raise () from /lib/libc.so.6
#4 0xb7d4030d in abort () from /lib/libc.so.6
#5 0xb7d715bc in __fsetlocking () from /lib/libc.so.6
#6 0xb7d7b417 in mallopt () from /lib/libc.so.6
#7 0xb7d7a0df in mallopt () from /lib/libc.so.6
#8 0xb7d78ccf in free () from /lib/libc.so.6
#9 0xb6bdbfce in gdFree () from /usr/lib/libgd.so.2
#10 0x09b6f96c in ?? ()
#11 0x00001249 in ?? ()
#12 0xb6de479c in ?? () from /usr/lib/perl5/vendor_perl/5.8.6/i686-linux/auto/GD/GD.so
#13 0xb6dd57b7 in XS_GD__Image_png () from /usr/lib/perl5/vendor_perl/5.8.6/i686-linux/auto/GD/GD.s
+o
#14 0x0827b548 in ?? ()
#15 0xb791b424 in PL_utf8_tolower () from /usr/lib/libperl.so.1
#16 0x00001249 in ?? ()
#17 0xb791199c in ?? () from /usr/lib/libperl.so.1
#18 0x0995c1bc in ?? ()
===============================
The error message is:
===============================
*** glibc detected *** free(): invalid pointer: 0x09be380c ***
[Sat Dec 24 17:55:26 2005] [notice] child pid 16836 exit signal Aborted (6)
===============================
Or:
===============================
[Sat Dec 24 18:06:13 2005] [notice] child pid 16838 exit signal Segmentation fault (11)
===============================
I removed the gdFree(data) from the perl module (GD.xs) and now it runs fine... But probably with a memory leak...
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<snip>
#ifdef HAVE_PNG
SV*
gdpng(image, ...)
GD::Image image
PROTOTYPE: $;$
PREINIT:
SV* errormsg;
CODE:
{
void* data;
int size;
int level;
if (items > 1) {
level = (int)SvIV(ST(1));
data = (void *) gdImagePngPtrEx(image,&size,level);
} else {
data = (void *) gdImagePngPtr(image,&size);
}
RETVAL = newSVpv((char*) data,size);
<br>gdFree(data); // <==== remove this and everything does run fine...</b>
}
OUTPUT:
RETVAL
#endif
<snip>
===============================
Any suggestions? I can't find the bug but I do think it has to do with freeing memory that is not allocated. Does gdImagePngPtr() realy always allocate memory?
MAG,
Milo
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