[xml/sgml-pkgs] Bug#590934: Bug#590934: libxml2: Segmentation fault, when compiling with -static

[Mike Hommey]

On Fri, Jul 30, 2010 at 11:53:17AM +0200, Christoph Junghans <junghans at votca.org> wrote:
> Package: libxml2
> Version: 2.6.32.dfsg-5+lenny1
> 
> I know static compiling is bad, but from time to time you need it.
> 
> Here is the simplest case I can imagine:
> $ cat main.c
> #include <libxml/parser.h>
> 
> int main(int argc, char **argv) {
>             xmlInitParser();
> }
> $ gcc -static main.c `xml2-config --libs --cflags` -pthread -lz -lm
> $ ./a.out
> Segmentation fault
> 
> This is a problem with weak symbols in threads.c
> 
> A patch can be found here:
> https://bugzilla.gnome.org/show_bug.cgi?id=609926
> but upstream refused to merge it.

Upstream is partially responsible for the problem. I'd say there are actually
2 different problems. The first one is that despite using weak symbols, the
initialization steps don't check if the symbols are resolved before using
them. That should IMHO be fixed in libxml2, instead of removing weak symbols.
The fix should be straightforward.

The other issue is that gcc and ld are doing weird stuff with those weak
pthread symbols, even when using -lpthread. I'll probably file a bug against
either or both.

Please also note that you should be using the "--libs --static" options when
linking statically libxml2, which gives the right flags, but due to the above,
that doesn't buy much.

Cheers,

Mike