Re: [PATCH] mm: idle-page: fix oops because end_pfn is larger than max_pfn
From: Vladimir Davydov
Date: Tue Jun 18 2019 - 16:08:02 EST
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>