Re: [PATCH v4] mm/ksm: Fix NULL pointer dereference when KSM zero page is enabled

[Joe Perches]

On Thu, 2020-04-16 at 14:20 +0300, Kirill Tkhai wrote:
> On 16.04.2020 09:14, Markus Elfring wrote:
> > â
> > > > +++ b/mm/ksm.c
> > > > @@ -2112,8 +2112,15 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
> > â
> > > > +		if (vma)
> > > > +			err = try_to_merge_one_page(vma, page,
> > > > +					ZERO_PAGE(rmap_item->address));
> > > > +		else
> > > > +			/**
> > > > +			 * If the vma is out of date, we do not need to
> > > > +			 * continue.

trivia:

It's generally better to not use "/**" as that's used for kernel-doc
and this could be a single line like

+			/* If the vma is out of date, no need to continue */

> > > It's conventional to put braces around multi-line blocks such as this.

true

> > Are there different views to consider around the usage of single statements
> > together with curly brackets in if branches?

no