Date: Tue, 13 Oct 2009 19:03:31 +0100 (BST)
From: Hugh Dickins <hugh.dickins@tiscali.co.uk>
To: Andi Kleen <andi@firstfloor.org>
cc: Wu Fengguang <fengguang.wu@intel.com>, Izik Eidus <ieidus@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] hwpoison: fix oops on ksm pages
In-Reply-To: <20091013154356.GA2127@basil.fritz.box>
Message-ID: <Pine.LNX.4.64.0910131855290.6481@sister.anvils>
References: <Pine.LNX.4.64.0910131451280.4698@sister.anvils>
 <20091013154356.GA2127@basil.fritz.box>
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On Tue, 13 Oct 2009, Andi Kleen wrote:
> On Tue, Oct 13, 2009 at 03:02:11PM +0100, Hugh Dickins wrote:
> > Memory failure on a KSM page currently oopses on its NULL anon_vma in
> > page_lock_anon_vma(): that may not be much worse than the consequence
> > of ignoring it, but it is better to be consistent with how ZERO_PAGE
> > and hugetlb pages and other awkward cases are treated.  Just skip it.
> 
> Thanks, Hugh. I'm curious: did this come out of code review or
> did you actually run into that?

Just out of code review: well, that's too fancy a name for it, I merely
remembered that I hadn't looked at ksm/hwpoison interoperabilty, so did
so just now.  After looking at the code, I did then try MADV_HWPOISON on
a MADV_MERGEABLE area, to check that the problem and the fix were real.

Hugh
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