From: Nick Piggin <npiggin@kernel.dk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Hugh Dickins <hughd@google.com>, Nick Piggin <npiggin@kernel.dk>,
Nick Bowler <nbowler@elliptictech.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-nfs@vger.kernel.org, Rik van Riel <riel@redhat.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: Fri, 3 Dec 2010 20:12:12 +1100 [thread overview]
Message-ID: <20101203091212.GA3346@amd> (raw)
In-Reply-To: <AANLkTinpvMJsC2XMUyDTaAdozFBLkcdde5_V57Jx-Z4w@mail.gmail.com>
On Wed, Dec 01, 2010 at 05:42:08PM -0800, Linus Torvalds wrote:
> On Wed, Dec 1, 2010 at 5:22 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > What we're talking about is races against memory reclaim, unmount, etc.
>
> Ahh. Those I can believe in.
Yeah, it's a tricky question. It would be solved if the inode reclaim
code didn't have the nasty shortcuts for nr_pages == 0 sitting outisde
the tree_lock... any time we have these kinds of optimisations checking
things outside locks, we invaraibly find they have races or data races
:(
So doing those checks under lock would be a reasonable way to fix it
if anyone cares for 2.6.37 or earlier (eg. distros). But it is another
lock in inode freeing path which is nice to avoid, so let's just get
it fixed with RCU in 2.6.38.
> Although I think they'd almost
> incidentally be fixed by making inode freeing (which is where the
> 'struct address_space' is embedded) RCU-safe, which we're going to do
> anyway in 38. Then we could make the vmscan code just be a rcu-read
> section.
Yep, good observation.
Thanks,
Nick
next prev parent reply other threads:[~2010-12-03 9:17 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
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 ` Nick Piggin [this message]
2010-12-01 23:43 ` [PATCH v2 " 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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