On Wed, Jul 17, 2024 at 05:05:55PM +0200, Nirmoy Das wrote:
>
> On 7/12/2024 11:41 PM, Jonathan Cavitt wrote:
> > Prevent a NULL pointer access in intel_memory_regions_hw_probe.
> >
> > Fixes: 05da7d9f717b ("drm/i915/gem: Downgrade stolen lmem setup warning")
> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > Signed-off-by: Jonathan Cavitt <jonathan.cavitt@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/intel_memory_region.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
> > index 172dfa7c3588b..d40ee1b42110a 100644
> > --- a/drivers/gpu/drm/i915/intel_memory_region.c
> > +++ b/drivers/gpu/drm/i915/intel_memory_region.c
> > @@ -368,8 +368,10 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
> > goto out_cleanup;
> > }
> > - mem->id = i;
> > - i915->mm.regions[i] = mem;
>
> There is a check for mem just before that. You could use IS_ERR_OR_NULL(mem)
> instead of IS_ERR().
An error pointer return is normally completely different from a NULL
return in how it's handled. Here NULL is a special kind of success. I
wrote a blog about this.
https://staticthinking.wordpress.com/2022/08/01/mixing-error-pointers-and-null/
regards,
dan carpenter
