Re: [cocci] Spatch corrupting struct variable

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Thu, 21 Dec 2023, Julia Lawall wrote:
> On Thu, 21 Dec 2023, Ilpo Järvinen wrote:
> 
> > Hi all,
> >
> > I'm at total loss what coccinelle/spatch is trying to do here:
> >
> > @@
> > struct resource *res;
> > expression size;
> > @@
> > - res->end = res->start + size - 1;
> > + resource_set_size(res, size);
> >
> > Spatching against Linux kernel tree results in this corruption:
> >
> > HANDLING: drivers/bus/fsl-mc/fsl-mc-bus.c
> > diff =
> > diff -u -p a/fsl-mc-bus.c b/fsl-mc-bus.c
> > --- a/fsl-mc-bus.c
> > +++ b/fsl-mc-bus.c
> > @@ -736,7 +736,7 @@ static int fsl_mc_device_get_mmio_region
> >                         goto error_cleanup_regions;
> >                 }
> >
> > -               regions[i].end = regions[i].start + region_desc.size - 1;
> > +               resource_set_size(regions, region_desc.size);
> >                 regions[i].name = "fsl-mc object MMIO region";
> >                 regions[i].flags = region_desc.flags & IORESOURCE_BITS;
> >                 regions[i].flags |= IORESOURCE_MEM;
> >
> > ??? How did that [i] vanish from regions? Why spatch thought . and -> are
> > equal?
> 
> There is an isomorphism that does that.  Maybe it should be removed...
> 
> In any case, you can put @disable ptr_to_array@ in place of the initial @@
> in your rule.  Or if your rule has a name, put the disable ptr_to_array
> after the name.

Thanks for the quick reply. Adding disable ptr_to_array indeed helped. :-)

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 i.