From: Rik van Riel <riel@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>,
Nick Bowler <nbowler@elliptictech.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-nfs@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Christoph Hellwig <hch@lst.de>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir
Date: Wed, 01 Dec 2010 12:02:06 -0500 [thread overview]
Message-ID: <4CF67F8E.6050308@redhat.com> (raw)
In-Reply-To: <AANLkTinwrhUOQ0LnavQY6+TQS_TqnRS0q-XXykZ8ap5G@mail.gmail.com>
On 12/01/2010 11:47 AM, Linus Torvalds wrote:
> On Wed, Dec 1, 2010 at 8:35 AM, Rik van Riel<riel@redhat.com> wrote:
>>
>> Surely somebody can have just looked up the page and
>> gotten a reference count, right before your ->freepage
>> call is invoked?
>
> No.
>
> The removal from the page cache is atomic, even in the presence of the
> lockless lookup.
>
> The page cache lookup does a "get_page_unless_zero()" on the count, so
> when __remove_mapping() has removed the page using
> "page_freeze_refs()", it's really gone, and cannot be looked up.
Doh, you're right. I forgot to look at all the stuff that
__remove_mapping does nowadays and remembered some very old
code from vmscan.c instead.
Acked-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
next prev parent reply other threads:[~2010-12-01 17:02 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-30 17:42 [PATCH] NFS: Fix a readdirplus bug Trond Myklebust
2010-11-30 22:10 ` Linus Torvalds
2010-11-30 22:13 ` Trond Myklebust
2010-12-01 3:47 ` [PATCH 0/3] Fix more NFS readdir regressions Trond Myklebust
2010-12-01 3:47 ` [PATCH 1/3] NFS: Ensure we use the correct cookie in nfs_readdir_xdr_filler Trond Myklebust
2010-12-01 15:04 ` Nick Bowler
2010-12-01 15:36 ` [PATCH v2 0/3] Fix more NFS readdir regressions Trond Myklebust
2010-12-01 15:36 ` [PATCH v2 1/3] NFS: Ensure we use the correct cookie in nfs_readdir_xdr_filler Trond Myklebust
2010-12-01 15:36 ` [PATCH v2 2/3] NFS: lock the readdir page while it is in use Trond Myklebust
2010-12-01 15:36 ` [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir Trond Myklebust
2010-12-01 16:17 ` Linus Torvalds
2010-12-01 16:35 ` Rik van Riel
2010-12-01 16:45 ` Benny Halevy
2010-12-01 16:47 ` Linus Torvalds
2010-12-01 17:02 ` Rik van Riel [this message]
2010-12-01 17:58 ` Trond Myklebust
2010-12-01 18:29 ` Miklos Szeredi
2010-12-01 18:54 ` Trond Myklebust
2010-12-01 19:23 ` Hugh Dickins
2010-12-01 19:52 ` Linus Torvalds
2010-12-01 20:05 ` Trond Myklebust
2010-12-01 20:39 ` Andrew Morton
2010-12-01 21:29 ` Neil Brown
2010-12-01 22:43 ` Andrew Morton
2010-12-01 23:01 ` Neil Brown
2010-12-01 19:47 ` Linus Torvalds
2010-12-01 20:10 ` Trond Myklebust
2010-12-01 20:18 ` Linus Torvalds
2010-12-01 20:31 ` Hugh Dickins
2010-12-01 20:33 ` Andrew Morton
2010-12-01 21:02 ` Hugh Dickins
2010-12-01 21:15 ` Hugh Dickins
2010-12-01 21:38 ` Andrew Morton
2010-12-01 21:51 ` Trond Myklebust
2010-12-01 22:13 ` Andrew Morton
2010-12-01 22:24 ` Linus Torvalds
2010-12-01 22:38 ` Andrew Morton
2010-12-01 22:47 ` Trond Myklebust
2010-12-01 23:21 ` Trond Myklebust
2010-12-01 23:46 ` Andrew Morton
2010-12-01 23:56 ` Trond Myklebust
2010-12-01 23:31 ` Linus Torvalds
2010-12-01 23:36 ` Andrew Morton
2010-12-02 1:05 ` Linus Torvalds
2010-12-02 1:22 ` Andrew Morton
2010-12-02 1:42 ` Linus Torvalds
2010-12-02 2:05 ` Andrew Morton
2010-12-02 3:08 ` [PATCH v3 0/3] Fix more NFS readdir regressions Trond Myklebust
2010-12-02 3:08 ` [PATCH v3 1/3] NFS: Ensure we use the correct cookie in nfs_readdir_xdr_filler Trond Myklebust
2010-12-02 3:08 ` [PATCH v3 2/3] Call the filesystem back whenever a page is removed from the page cache Trond Myklebust
2010-12-02 3:34 ` Hugh Dickins
2010-12-02 3:53 ` Trond Myklebust
2010-12-02 3:58 ` Linus Torvalds
2010-12-06 16:59 ` [PATCH v4 0/3] Fix more NFS readdir regressions Trond Myklebust
2010-12-06 16:59 ` [PATCH v4 1/3] NFS: Ensure we use the correct cookie in nfs_readdir_xdr_filler Trond Myklebust
2010-12-06 16:59 ` [PATCH v4 2/3] Call the filesystem back whenever a page is removed from the page cache Trond Myklebust
2010-12-07 7:08 ` Nick Piggin
2010-12-06 16:59 ` [PATCH v4 3/3] NFS: Fix a memory leak in nfs_readdir Trond Myklebust
2010-12-02 3:08 ` [PATCH v3 " Trond Myklebust
2010-12-03 9:12 ` [PATCH v2 " Nick Piggin
2010-12-01 23:43 ` Trond Myklebust
2010-12-01 22:43 ` Hugh Dickins
2010-12-01 3:47 ` [PATCH 2/3] NFS: lock the readdir page while it is in use Trond Myklebust
2010-12-01 4:10 ` Linus Torvalds
2010-12-01 4:29 ` Trond Myklebust
2010-12-01 5:06 ` Linus Torvalds
2010-12-01 14:49 ` Trond Myklebust
2010-12-01 13:14 ` Rik van Riel
2010-12-01 14:55 ` Trond Myklebust
2010-12-01 3:47 ` [PATCH 3/3] NFS: Fix a memory leak in nfs_readdir Trond Myklebust
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