Witold Baryluk wrote:
> why suppressing this error, it is probably real problem
> in libz.
What makes you say that? The zlib FAQ says:
| 36. Valgrind (or some similar memory access checker) says that deflate is
| performing a conditional jump that depends on an uninitialized value.
| Isn't that a bug?
|
| No. That is intentional for performance reasons, and the output of
| deflate is not affected. This only started showing up recently since
| zlib 1.2.x uses malloc() by default for allocations, whereas earlier
| versions used calloc(), which zeros out the allocated memory.
zlib 1.2.3.7 eliminated the access of unitialized memory you mention,
using the following patch:
| diff --git a/inflate.c b/inflate.c
| index 40c0ec8b..a8431abe 100644
| --- a/inflate.c
| +++ b/inflate.c
| @@ -1,5 +1,5 @@
| /* inflate.c -- zlib decompression
| - * Copyright (C) 1995-2009 Mark Adler
| + * Copyright (C) 1995-2010 Mark Adler
| * For conditions of distribution and use, see copyright notice in zlib.h
| */
|
| @@ -154,7 +154,7 @@ int windowBits;
| /* set number of window bits, free window if different */
| if (windowBits && (windowBits < 8 || windowBits > 15))
| return Z_STREAM_ERROR;
| - if (state->wbits != (unsigned)windowBits && state->window != Z_NULL) {
| + if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
| ZFREE(strm, state->window);
| state->window = Z_NULL;
| }
As you can see, the output is not affected.
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