linux-kernel - Re: [PATCH 09/22] HWPOISON: Handle hardware poisoned pages in try_to

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20090616090308.bac3b1f7.minchan.kim@barrios-desktop>
Date:	Tue, 16 Jun 2009 09:03:08 +0900
From:	Minchan Kim <minchan.kim@...il.com>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	Minchan Kim <minchan.kim@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andi Kleen <ak@...ux.intel.com>, Ingo Molnar <mingo@...e.hu>,
	Mel Gorman <mel@....ul.ie>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Nick Piggin <npiggin@...e.de>,
	Hugh Dickins <hugh.dickins@...cali.co.uk>,
	Andi Kleen <andi@...stfloor.org>,
	"riel@...hat.com" <riel@...hat.com>,
	"chris.mason@...cle.com" <chris.mason@...cle.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH 09/22] HWPOISON: Handle hardware poisoned pages in
 try_to_unmap

On Mon, 15 Jun 2009 23:26:12 +0800
Wu Fengguang <fengguang.wu@...el.com> wrote:

> On Mon, Jun 15, 2009 at 09:09:03PM +0800, Minchan Kim wrote:
> > On Mon, Jun 15, 2009 at 11:45 AM, Wu Fengguang<fengguang.wu@...el.com> wrote:
> > > From: Andi Kleen <ak@...ux.intel.com>
> > >
> > > When a page has the poison bit set replace the PTE with a poison entry.
> > > This causes the right error handling to be done later when a process runs
> > > into it.
> > >
> > > Also add a new flag to not do that (needed for the memory-failure handler
> > > later)
> > >
> > > Reviewed-by: Wu Fengguang <fengguang.wu@...el.com>
> > > Signed-off-by: Andi Kleen <ak@...ux.intel.com>
> > >
> > > ---
> > >  include/linux/rmap.h |    1 +
> > >  mm/rmap.c            |    9 ++++++++-
> > >  2 files changed, 9 insertions(+), 1 deletion(-)
> > >
> > > --- sound-2.6.orig/mm/rmap.c
> > > +++ sound-2.6/mm/rmap.c
> > > @@ -958,7 +958,14 @@ static int try_to_unmap_one(struct page
> > >        /* Update high watermark before we lower rss */
> > >        update_hiwater_rss(mm);
> > >
> > > -       if (PageAnon(page)) {
> > > +       if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
> > > +               if (PageAnon(page))
> > > +                       dec_mm_counter(mm, anon_rss);
> > > +               else if (!is_migration_entry(pte_to_swp_entry(*pte)))
> > 
> > Isn't it straightforward to use !is_hwpoison_entry ?
> 
> Good catch!  It looks like a redundant check: the
> page_check_address() at the beginning of the function guarantees that 
> !is_migration_entry() or !is_migration_entry() tests will all be TRUE.
> So let's do this?
It seems you expand my sight :)

I don't know migration well.
How page_check_address guarantee it's not migration entry ? 

In addtion, If the page is poison while we are going to migration((PAGE_MIGRATION && migration) == TRUE), we should decrease file_rss ?

> 
> -               else if (!is_migration_entry(pte_to_swp_entry(*pte)))
> +               else
> 
> 
> Thanks,
> Fengguang


-- 
Kinds Regards
Minchan Kim
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/