Nouveau - Dec 2016 - [bug report] drm/nouveau/imem: convert to new-style nvkm_subdev

[ No idea why it's only complaining about this a year later... -dan ]

Hello Ben Skeggs,

This is a semi-automatic email about new static checker warnings.

The patch b7a2bc1886d0: "drm/nouveau/imem: convert to new-style 
nvkm_subdev" from Aug 20, 2015, leads to the following Smatch 
complaint:

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c:536 gk20a_instobj_new()
	 error: we previously assumed 'node' could be null (see line 532)

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
   531						     align, &node);
   532		*pmemory = node ? &node->memory : NULL;
                           ^^^^
Added a new check for NULL.

   533		if (ret)
   534			return ret;
   535	
   536		node->imem = imem;
                ^^^^^^^^^^
Unchecked dereference.

   537	
   538		/* present memory for being mapped using small pages */

regards,
dan carpenter

If ret == 0, then node should not be null. Either that no longer holds, or
your static checker is no longer able to deduce that.

On Dec 12, 2016 7:07 AM, "Dan Carpenter" <dan.carpenter at
oracle.com> wrote:
> [ No idea why it's only complaining about this a year later... -dan ]
>
> Hello Ben Skeggs,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch b7a2bc1886d0: "drm/nouveau/imem: convert to new-style
> nvkm_subdev" from Aug 20, 2015, leads to the following Smatch
> complaint:
>
> drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c:536
> gk20a_instobj_new()
>          error: we previously assumed 'node' could be null (see
line 532)
>
> drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
>    531                                               align, &node);
>    532          *pmemory = node ? &node->memory : NULL;
>                            ^^^^
> Added a new check for NULL.
>
>    533          if (ret)
>    534                  return ret;
>    535
>    536          node->imem = imem;
>                 ^^^^^^^^^^
> Unchecked dereference.
>
>    537
>    538          /* present memory for being mapped using small pages */
>
> regards,
> dan carpenter
> _______________________________________________
> Nouveau mailing list
> Nouveau at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.freedesktop.org/archives/nouveau/attachments/20161212/83d46172/attachment.html>