Re: [xml] Memory Bug detection for gdome

[Daniel Veillard <veillard redhat com>]

On Wed, Mar 02, 2011 at 09:10:47AM +0100, Alexandre Gouraud wrote:
> Hello,
>
> I am currently trying to run gdome tests under cygwin but get segfaults.
> Since I can't find with the debuger where the memory corruption occurs, I
> tried to use the memory allocation hooks provided by the library. I have
> written my own very simple memory allocator: One big chunk of memory is
> allocated at first, and then pieces of this big chunk are provided on
> demand. The memory is never freed (and I never run out of memory in this
> particular case). I setup this memory allocator with:
>
> xmlMemSetup(myFree, myMalloc, myRealloc,xmlMemStrdup);
>
> And put this at the very begining of the test.
>
> I get the results below. I was expecting the "Malloc at 0x... of ..." which
> are produced by my own memory allocation routines. But I was not expecting
> this
>
> "Memory tag error occurs: 0x...
> bye
> xmlMemFree(...) error"
>
> Which indicates that not all memory allocation routines have been hooked. I
> suspect this is internal to the libxml. could this indicate a memory bug in
> the library ?
> I have libxml2 version 2.7.7

  I compile and run libxml2 with full regression tests using the memory
debug, so I doubt it's a libxml2 issue. But if gdome modify the tree
with a piece of memory allocated by malloc and then tries to free the
tree you will get this problem.

Daniel

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