Re: [Pkg-octave-devel] Bug#394982: octave2.9: Crashes on "x(:, :)=speye(1)"

[David Bateman]

Rafael Laboissiere wrote:
> * David Bateman <address@hidden> [2006-10-24 14:18]:
>
>   
> > Thomas Weber wrote:
> >     
> > > Hi, 
> > >
> > > Am Dienstag, den 24.10.2006, 12:55 +0200 schrieb Rafael Laboissiere:
> > >  
> > >       
> > > > > address@hidden:~/orion/trunk/solver$ octave -q
> > > > > octave:1> x(:,:)=speye(1);
> > > > > panic: Segmentation fault -- stopping myself...
> > > > > Segmentation fault
> > > > > address@hidden:~/orion/trunk/solver$
> > > > >      
> > > > >           
> > > I tried this with CVS and it crashes as well:
> > >
> > > ==================================================================
> > > octave-2.9.9+:1> x(:,:)=speye(1);
> > > *** glibc detected *** free(): invalid next size (fast): 
> > > 0x0000000001611150 ***
> > > panic: Aborted -- stopping myself...
> > > attempting to save variables to `octave-core'...
> > > save to `octave-core' complete
> > > Aborted
> > > ==================================================================
> > >
> > >         Thomas
> > >
> > >  
> > >       
> > I just tried this with a CVS from Sunday on an Mandriva 2006 system and 
> > could not generate that same error..
> >     
>
> This works in my Debian etch system with octave2.9-2.9.9-3::
>
>     octave2.9:1> speye (1);
>     octave2.9:2> x = speye (1);
>
> But this don't:
>
>     octave2.9:1> x (:, :) = speye (1);
>     panic: Segmentation fault -- stopping myself...
>     *** glibc detected *** malloc(): memory corruption (fast): 0x0904d970 ***
>     panic: attempted clean up apparently failed -- aborting...
>     Aborted
>
> There is something weird with the indexing operation on the lefthand side
> when the variable being assigned is undefined.  For instance, this works:
>
>     octave2.9:1> x = speye (1);
>     octave2.9:2> x (:, :) = speye (1);
>
> At any rate, the malloc problem reported in the error message may indicate
> some Debian-specific bug.
>
>   

My fault, I can generate the problem. I did

x(:,:) = eye(1)
x(:,:) = speye(1)

instead...

D.