[GRASS-dev] Re: [GRASS GIS] #50: g.copy segfaults
(debian.gfoss.it package) [and latest SVN]
Dylan Beaudette
dylan.beaudette at gmail.com
Fri Apr 11 18:25:27 EDT 2008
On Friday 11 April 2008, Glynn Clements wrote:
> GRASS GIS wrote:
> > #50: g.copy segfaults (debian.gfoss.it package) [and latest SVN]
> > ----------------------+--------------------------------------------------
> >--- Reporter: steko | Owner: grass-dev at lists.osgeo.org
> > Type: defect | Status: new
> > Priority: major | Milestone: 6.4.0
> > Component: default | Version: 6.3.0 RCs
> > Resolution: | Keywords: g.copy
> > ----------------------+--------------------------------------------------
> >--- Changes (by dylan):
> >
> > * summary: g.copy segfaults (debian.gfoss.it package) => g.copy
> > segfaults (debian.gfoss.it package) [and latest
> > SVN]
> >
> > Comment:
> >
> > Ouch. This bug has been biting me for a while now. How can optimization
> > cause a segfault for {{{g.copy rast=rast1,rast2}}} but not for {{{g.copy
> > vect=vect1,vect2}}} ?
>
> For vectors, the copying is performed by calling Vect_copy(). For all
> other types, g.copy copies the files itself.
OK.
>
> > This sounds like a nasty bug to me.
>
> Unfortunately, it isn't likely to get fixed unless someone who can get
> the segfault to occur can debug it, at least to the extent of
> identifying exactly where the segfault occurs.
Dang! I have seen the bug for a number of months now, across operating systems
and architectures. For starters, here are the GCC optimization flags:
http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
> As it only occurs with optimisation enabled, it will probably need to
> be debugged in assembler ("set language asm"), as GDB cannot reliably
> relate execution to the source code for optimised code (the structure
> of optimised code often bears little resemblence to the source code).
Yikes. Can't really do that.
I will post some details to the original ticket.
Dylan
--
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341
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