question regarding nvc0_instmem_suspend()

[Luca Tettamanti]

On Fri, Aug 13, 2010 at 11:39 PM, Dan Carpenter <error27 at gmail.com> wrote:
> Smatch thinks there is a buffer overflow in nvc0_instmem_suspend() and
> I've looked at it, but I don't understand the code.
>
> drivers/gpu/drm/nouveau/nvc0_instmem.c +152 nvc0_instmem_suspend(10)
>        error: buffer overflow 'dev_priv->susres.ramin_copy' 16384 <= 1835008
>
>   141  int
>   142  nvc0_instmem_suspend(struct drm_device *dev)
>   143  {
>   144          struct drm_nouveau_private *dev_priv = dev->dev_private;
>   145          int i;
>   146
>   147          dev_priv->susres.ramin_copy = vmalloc(65536);
>
>        dev_priv->susres.ramin_copy is an array of 16384 u32 elements
>        (65536 bytes).
>
>   148          if (!dev_priv->susres.ramin_copy)
>   149                  return -ENOMEM;
>   150
>   151          for (i = 0x700000; i < 0x710000; i += 4)
>   152                  dev_priv->susres.ramin_copy[i/4] = nv_rd32(dev, i);
>
>        0x700000 / 4 is 1835008 so we're way past the end of the array
>        and then we get larger.

I guess that it should be something like:

    base = 0x700000;
    for (i = 0; i < 0x10000; i += 4)
        dev_priv->susres.ramin_copy[i/4] = nv_rd32(dev, base + i);


Luca