Re: [PATCH v2] mm: cma: fix CMA aligned offset calculation

From: Danesh Petigara
Date: Fri Feb 27 2015 - 20:07:37 EST


On 2/27/2015 3:54 PM, Andrew Morton wrote:
> On Fri, 27 Feb 2015 15:52:56 -0800 Danesh Petigara <dpetigara@xxxxxxxxxxxx> wrote:
>
>> On 2/27/2015 1:24 PM, Andrew Morton wrote:
>>> On Tue, 24 Feb 2015 15:39:45 -0800 Danesh Petigara <dpetigara@xxxxxxxxxxxx> wrote:
>>>
>>>> The CMA aligned offset calculation is incorrect for
>>>> non-zero order_per_bit values.
>>>>
>>>> For example, if cma->order_per_bit=1, cma->base_pfn=
>>>> 0x2f800000 and align_order=12, the function returns
>>>> a value of 0x17c00 instead of 0x400.
>>>>
>>>> This patch fixes the CMA aligned offset calculation.
>>>
>>> When fixing a bug please always describe the end-user visible effects
>>> of that bug.
>>>
>>> Without that information others are unable to understand why you are
>>> recommending a -stable backport.
>>>
>>
>> Thank you for the feedback. I had no crash logs to show, nevertheless, I
>> agree that a sentence describing potential effects of the bug would've
>> helped.
>
> What was the reason for adding a cc:stable?
>

It was added since the commit that introduced the incorrect logic
(b5be83e) was already picked up by v3.19.

Thanks,
Danesh
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