Re: [PATCH v2] staging: zsmalloc: Ensure handle is never 0 on success

From: Greg KH
Date: Tue Nov 19 2013 - 18:26:32 EST


On Tue, Nov 12, 2013 at 09:06:37AM -0800, Olav Haugan wrote:
> Hi Greg,
>
> On 11/11/2013 4:19 PM, Greg KH wrote:
> > On Thu, Nov 07, 2013 at 05:58:03PM -0800, Olav Haugan wrote:
> >> zsmalloc encodes a handle using the pfn and an object
> >> index. On hardware platforms with physical memory starting
> >> at 0x0 the pfn can be 0. This causes the encoded handle to be
> >> 0 and is incorrectly interpreted as an allocation failure.
> >
> > Please list the known hardware platforms that have this issue, so that
> > people have a chance to know if this patch is relevant for them or not.
> >
> > For example, should I include this in the stable releases because it
> > affects systems that are shipping? Or is it just in "future" chips and
> > it doesn't need to go there or not?
> >
> > Please make it easy for me to do this type of determination, I already
> > asked you this question before, why didn't you include the information
> > here as well (hint, that is why I asked you...)
>
> I don't think it would be the best to mention specific hardware
> platforms in the commit text. If I saw this patch listing specific
> hardware platforms I would have made the wrong decision (I would look at
> the list and decide that I am not running on those platforms so I don't
> need this patch). The problem could happen on any hardware platform. It
> just depends on how the memory map of the platform is configured. Hence,
> I re-worded the commit text to make it clear that this will happen when
> you have memory starting at 0x0.
>
> If I list out specific hardware platforms it would be only a sample (I
> do not know all hardware platforms and their memory maps). However,
> having said that there are products already shipping with physical
> address starting at 0.

Having something in there is better than nothing...

So, care to try it again?
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