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Date: Sun, 27 Jul 2008 08:35:21 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       Jan Kara <jack@ucw.cz>
Subject: Re: [PATCH] lost sysctl fix
Message-ID: <20080727063521.GA1963@elte.hu>
References: <14615.1217125366@turing-police.cc.vt.edu> <20080726202525.3ac3052f.akpm@linux-foundation.org> <21657.1217130229@turing-police.cc.vt.edu> <20080727040908.GX28946@ZenIV.linux.org.uk> <20080727051702.GY28946@ZenIV.linux.org.uk> <20080727053122.GZ28946@ZenIV.linux.org.uk> <20080727062956.GA24749@elte.hu>
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* Ingo Molnar <mingo@elte.hu> wrote:

> 
> * Al Viro <viro@ZenIV.linux.org.uk> wrote:
> 
> > try_attach() should walk into the matching subdirectory, not the first one...
> > 
> > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> > ---
> > [and yes, that's what that crap had been]
> 
> does this explain the following crash -tip testing just triggered with 
> latest -git:
> 
> [   12.293289] calling  butterfly_init+0x0/0x14
> [   12.298036] BUG: unable to handle kernel NULL pointer dereference at 00000004
> [   12.302065] IP: [<c012c169>] __register_sysctl_paths+0x1af/0x253
> [   12.308058] *pdpt = 0000000000b81001 *pde = 0000000000000000 
> [   12.314809] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC

your patch fixes it.

Tested-by: Ingo Molnar <mingo@elte.hu>

	Ingo