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

Olav Haugan
2013-11-07T22:57:12Z

On 11/6/2013 7:06 PM, Greg KH wrote:
> On Wed, Nov 06, 2013 at 04:00:02PM -0800, Olav Haugan wrote:
>> On 11/5/2013 5:56 PM, Greg KH wrote:
>>> On Tue, Nov 05, 2013 at 04:54:12PM -0800, Olav Haugan wrote:
>>>> zsmalloc encodes a handle using the page pfn and an object
>>>> index. On some hardware platforms the pfn could be 0 and this
>>>> causes the encoded handle to be 0 which is interpreted as an
>>>> allocation failure.
>>>
>>> What platforms specifically have this issue?
>>
>> Currently some of Qualcomm SoC's have physical memory that starts at
>> address 0x0 which causes this problem.
>
> Then say this, and list the exact SoC's that can have this problem so
> people know how to evaluate the bugfix and see if it is relevant for
> their systems.
>
>> I believe this could be a problem
>> on any platforms if memory is configured to be starting at physical
>> address 0x0 for these platforms.
>
> Have you seen this be a problem? So it's just a theoretical issue at
> this point in time?

Yes, I can consistently reproduce it. It is not just theoretical.

Thanks,

Olav Haugan

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