Re: [PATCH v2] mm: include CMA pages in lowmem_reserve at boot

[Florian Fainelli]

On 8/19/20 10:22 AM, Andrew Morton wrote:
> On Wed, 19 Aug 2020 10:15:53 -0700 Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
> 
>>>> In many cases the difference is not significant, but for example
>>>> an ARM platform with 1GB of memory and the following memory layout
>>>> [    0.000000] cma: Reserved 256 MiB at 0x0000000030000000
>>>> [    0.000000] Zone ranges:
>>>> [    0.000000]   DMA      [mem 0x0000000000000000-0x000000002fffffff]
>>>> [    0.000000]   Normal   empty
>>>> [    0.000000]   HighMem  [mem 0x0000000030000000-0x000000003fffffff]
>>>>
>>>> would result in 0 lowmem_reserve for the DMA zone. This would allow
>>>> userspace to deplete the DMA zone easily.
>>>
>>> Sounds fairly serious for thos machines.  Was a cc:stable considered?
>>
>> Since there is a Fixes: tag, it may have been assumed that the patch
>> would be picked up and as soon as it reaches Linus' tree it would be
>> picked up by the stable selection.
> 
> It doesn't work that way - sometimes a fix isn't considered important
> enough to backport.  It could just fix a typo in a comment!

Then can this be applied ASAP and back ported?
-- 
Florian