Re: [bug-gv] [Fwd: Re: gv 3.6.7 segment violations on multiple platforms]

[Bernhard R. Link]

* Markus Steinborn <address@hidden> [090325 05:54]:
> I got the following reply. I dislike the lots of warnings before the 
> crash, they are not from valgrind... Any idea where they might come from?
>
> The valgrind run shows that we are operating on the null pointer, so 
> some Xaw3D-init is failing, too.

Indeed, there looks to be something fishy with the Xaw stuff.

> ==8931== Invalid read of size 1
> ==8931==    at 0x400804A: rawmemchr (mc_replace_strmem.c:585)
> ==8931==    by 0x3FCC2A: _IO_str_init_static_internal (in /lib/libc-2.9.so)
> ==8931==    by 0x3EFF72: vsscanf (in /lib/libc-2.9.so)
> ==8931==    by 0x3EA46A: sscanf (in /lib/libc-2.9.so)
> ==8931==    by 0x8057C5A: Initialize (Vlist.c:204)
> ==8931==    by 0x421E858: (within /usr/lib/libXt.so.6.0.0)
> ==8931==    by 0x421F36A: (within /usr/lib/libXt.so.6.0.0)
> ==8931==    by 0x421FCF4: _XtCreateWidget (in /usr/lib/libXt.so.6.0.0)
> ==8931==    by 0x421FFE3: XtCreateManagedWidget (in /usr/lib/libXt.so.6.0.0)
> ==8931==    by 0x8061975: main (main.c:1138)
> ==8931==  Address 0x0 is not stack'd, malloc'd or (recently) free'd

As Vlist.c:204 is:
sscanf(vw->vlist.highlighted_geometry,"%d %d %d %d", 
&(vw->vlist.hulx),&(vw->vlist.huly),&(vw->vlist.hlrx),&(vw->vlist.hlry));
I was already suspecting from the backtraces, that either the resources
are broken, or the sscanf. As it should be fairly impossible for the
user to get a NULL pointer in highlighted_geometry which has a default
value, I was more expecting that sscanf might be perhaps broken by the
alternative implementation, but this one has more information making it
less likely that sscanf is broken and the warnings of course make it
much more likely somehting in the resource handling is broken:

especially this one actively matches the problematic field:

> Warning: Representation size 4 must match superclass's to override 
> highlightedBackground

the rest indicates that this is not necessary some incompatible change,
but perhaps simply a totally broken xt implementation:

> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "on" to type Int
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Unsupported shape style for Command widget "toggleCurrent"
> Warning: Unsupported shape style for Command widget "toggleEven"
> Warning: Unsupported shape style for Command widget "toggleOdd"
> Warning: Unsupported shape style for Command widget "unmarkAll"
> Warning: Unsupported shape style for Command widget "autoResize"
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Cannot convert string "XtDefaultBackground" to type Pixel
> Warning: Representation size 2 must match superclass's to override 
> internalWidth

On the other hand, the xcb stuff indicates that this is a very
new-fangled X implementtion. who knows what else they might have
broken...

I think the most important information now is the exact versions of
libXt, libXaw and libXaw3d involved.

Hochachtungsvoll,
        Bernhard R. Link