Re: [PATCH] proc/kcore: Don't bounds check against address 0

[Laura Abbott]

On 05/01/2018 02:46 PM, Andrew Morton wrote:
> On Tue,  1 May 2018 13:11:43 -0700 Laura Abbott <labbott@xxxxxxxxxx> wrote:
>
> > The existing kcore code checks for bad addresses against
> > __va(0) with the assumption that this is the lowest address
> > on the system. This may not hold true on some systems (e.g.
> > arm64) and produce overflows and crashes. Switch to using
> > other functions to validate the address range.
> >
> > Tested-by: Dave Anderson <anderson@xxxxxxxxxx>
> > Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> > ---
> > I took your previous comments as a tested by, please let me know if that
> > was wrong. This should probably just go through -mm. I don't think this
> > is necessary for stable but I can request it later if necessary.
>
> I'm surprised.  "overflows and crashes" sounds rather serious??

It's currently only seen on arm64 and it's not clear if anyone
wants to use that particular combination on a stable release.
I think a better phrase is "this is not urgent for stable".

Thanks,
Laura