memory leak when deal with corrupted png: 6.7.9

[zhcn381]

hi, magick

I'm working on observing our production system's memory leak problem recently. Unfortunately I found another memory leak in ImageMagick. Although it's not a big deal, I still put it here to let you know. Again, it's a corrupted png. It also exists in early version like 6.2.8. I noticed that when the following setjmp is returned through longjmp, the value of ping_pixels will be NULL, so when you switch "gcc -O " on, the code which is responsible for releasing the resources is optimized by the compile.

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      if (ping_pixels != (unsigned char *) NULL)
        ping_pixels=(unsigned char *) RelinquishMagickMemory(ping_pixels);

Here is the patch, pls check it:

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Index: coders/png.c                                                                                                                   
===================================================================
--- coders/png.c  (revision 9547)
+++ coders/png.c  (working copy)
@@ -2038,7 +2038,7 @@
     x_resolution,
     y_resolution;

-  unsigned char
+  unsigned char volatile
     *ping_pixels;

   ssize_t

Again, I will upload the corrupted png here. I can't find where I can post an attachment.

[magick]

Thanks for the problem report and patch. We'll apply the patch to ImageMagick 6.8.0-0 Beta by sometime tomorrow.

[zhcn381]

hi, magick

I'm sorry. It's

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unsigned char  * volatile ping_pixels

not

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unsigned char volatile * ping_pixels

[magick]

Right we spotted that correction when we applied the patch. Thanks.