Patch from Vladimir Marangozov <marangoz@python.inrialpes.fr>
The same problem (mixed mallocs) exists for the pcre stack.
The buffers md->... are allocated via PyMem_RESIZE in grow_stack(),
while in free_stack() they are released with free() instead of
PyMem_DEL().
diff --git a/Modules/pypcre.c b/Modules/pypcre.c
index 976eb21..468751d 100644
--- a/Modules/pypcre.c
+++ b/Modules/pypcre.c
@@ -3057,12 +3057,12 @@
static int free_stack(match_data *md)
{
/* Free any stack space that was allocated by the call to match(). */
-if (md->off_num) free(md->off_num);
-if (md->offset_top) free(md->offset_top);
-if (md->r1) free(md->r1);
-if (md->r2) free(md->r2);
-if (md->eptr) free((char *)md->eptr);
-if (md->ecode) free((char *)md->ecode);
+if (md->off_num) PyMem_DEL(md->off_num);
+if (md->offset_top) PyMem_DEL(md->offset_top);
+if (md->r1) PyMem_DEL(md->r1);
+if (md->r2) PyMem_DEL(md->r2);
+if (md->eptr) PyMem_DEL((char *)md->eptr);
+if (md->ecode) PyMem_DEL((char *)md->ecode);
return 0;
}