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From: Balbir Singh <balbir@in.ibm.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
	Andrea Arcangeli <andrea@suse.de>,
	Petr Tesarik <ptesarik@suse.cz>, Hugh Dickins <hugh@veritas.com>
Subject: Re: [rfc][patch] rmap: more sanity checks
Date: Wed, 14 Feb 2007 22:22:25 +0530	[thread overview]
Message-ID: <45D33E49.8070909@in.ibm.com> (raw)
In-Reply-To: <20070214090425.GA14932@wotan.suse.de>

Nick Piggin wrote:
> We have seen a bug in SLES9 that only gets picked up with Andrea's extra
> rmap checks that were removed from mainline.
> 
> Petr Tesarik has got a fix for the problem, which he is planning to send
> upstream. The issue is a specific condition that causes an anon page to be
> incorrectly inserted into the pagetables, outside a valid vma.
> 
> It would be nice to get some of these checks back into mainline, IMO. I
> wonder if I'm correct in thinking that checking the page index and mapping
> is not actually racy?
> 

I hope so, if that is indeed the case my patches for tracking and accounting
shared rss pages at

http://marc.theaimsgroup.com/?l=linux-mm&m=116738715329816&w=2

will get much simpler.

There used to be a rmap lock (PG_maplock bit) earlier to protect
rmap information

Please see

http://marc.theaimsgroup.com/?l=linux-mm&m=116738715302690&w=2

and

http://lkml.org/lkml/2004/7/12/241


	Regards,
	Balbir Singh

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      parent reply	other threads:[~2007-02-14 17:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-14  9:04 [rfc][patch] rmap: more sanity checks Nick Piggin
2007-02-14 16:50 ` Andrea Arcangeli
2007-02-15  0:46   ` Nick Piggin
2007-02-14 16:52 ` Balbir Singh [this message]

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