Re: [PATCH] mm: idle-page: fix oops because end_pfn is larger than max_pfn

[Vladimir Davydov]

On Tue, Jun 18, 2019 at 12:45:02PM -0700, Andrew Morton wrote:
> On Tue, 18 Jun 2019 13:43:52 +0100 Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> 
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > 
> > Currently the calcuation of end_pfn can round up the pfn number to
> > more than the actual maximum number of pfns, causing an Oops. Fix
> > this by ensuring end_pfn is never more than max_pfn.
> > 
> > This can be easily triggered when on systems where the end_pfn gets
> > rounded up to more than max_pfn using the idle-page stress-ng
> > stress test:
> > 
> 
> cc Vladimir.  This seems rather obvious - I'm wondering if the code was
> that way for some subtle reason?

No subtle reason at all - just a bug. The patch looks good to me,

Acked-by: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>