linux-kernel - Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs

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Message-ID: <4CF67955.2050808@redhat.com>
Date:	Wed, 01 Dec 2010 11:35:33 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Trond Myklebust <Trond.Myklebust@...app.com>,
	Nick Bowler <nbowler@...iptictech.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-nfs@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>,
	Christoph Hellwig <hch@....de>,
	Al Viro <viro@...iv.linux.org.uk>
Subject: Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir

On 12/01/2010 11:17 AM, Linus Torvalds wrote:

> So this is a TOTALLY UNTESTED trivial patch that just adds another
> callback. Does this work? I dunno. But I get the feeling that instead
> of having NFS work around the odd semantics that don't actually match
> what NFS wants, introducing a new callback with much simpler semantics
> would be simpler for everybody, and avoid the need for subtle code.

Surely somebody can have just looked up the page and
gotten a reference count, right before your ->freepage
call is invoked?

CPU A				CPU B

look up page
grab refcount
				->freepage

use contents of page

Am I overlooking something obvious?

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