Re: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA

[Posted April 14, 2010 by corbet]

From:		Linus Torvalds <torvalds-AT-linux-foundation.org>
To:		Borislav Petkov <bp-AT-alien8.de>
Subject:		Re: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA
Date:		Mon, 12 Apr 2010 15:11:53 -0700 (PDT)
Cc:		Johannes Weiner <hannes-AT-cmpxchg.org>, KOSAKI Motohiro <kosaki.motohiro-AT-jp.fujitsu.com>, Rik van Riel <riel-AT-redhat.com>, Andrew Morton <akpm-AT-linux-foundation.org>, Minchan Kim <minchan.kim-AT-gmail.com>, Linux Kernel Mailing List <linux-kernel-AT-vger.kernel.org>, Lee Schermerhorn <Lee.Schermerhorn-AT-hp.com>, Nick Piggin <npiggin-AT-suse.de>, Andrea Arcangeli <aarcange-AT-redhat.com>, Hugh Dickins <hugh.dickins-AT-tiscali.co.uk>, sgunderson-AT-bigfoot.com



On Mon, 12 Apr 2010, Borislav Petkov wrote:
> 
> > I have a new theory. And this new theory is completely different from all 
> > the other things we've been looking at.
> 
> Yeah, because all starts with "I have a new theory..." :o)

Hey, all my other theories made sense too.. They just didn't work.

But as Edison said: I didn't fail, I just found three other ways to not 
fix your bug.

> > The patch below is my largely mindless try at fixing this. It's untested. 
> > I'm not entirely sure that it actually works. But it makes some amount of 
> > conceptual sense. No?
> 
> Linus, are you trying to give me a heart-attack? This sh*t just survived
> 20(!) hibernation runs without a problem (well, there is this nagging
> /sysfs lockdep warning) but apart from that, it survived! I even did my
> all time best when hitting on it. Normally, it used to crap up on the
> 6th cycle as latest. Now we're rock solid. And yes, there were something
> like ~64Mb in the swap cache.
> 
> Also, I have your verification stuff in addition to the 4 patches you
> sent before. Not a single WARN_ONCE got triggered. So I have a gut
> feeling that it is fixed but you never know with these beasts.

Ok. That does sound very positive. Of course, last time you sounded 
positive, I had an email from you half an hour later that said "oh no, it 
oopsed again". So I'll take it with a bit of salt, but on the whole I'll 
be optimistic about it.

				Linus