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From: Gao Xiang <hsiangkao@aol.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	hch@infradead.org, willy@infradead.org,
	Mike Marshall <hubcap@omnibond.com>,
	Martin Brandenburg <martin@omnibond.com>,
	devel@lists.orangefs.org
Subject: Re: [RFC PATCH 8/9] orangefs: use set/clear_fs_page_private
Date: Mon, 27 Apr 2020 11:27:07 +0800	[thread overview]
Message-ID: <20200427032658.GA4754@hsiangkao-HP-ZHAN-66-Pro-G1> (raw)
In-Reply-To: <20200427025752.GA3979@hsiangkao-HP-ZHAN-66-Pro-G1>

On Mon, Apr 27, 2020 at 10:58:02AM +0800, Gao Xiang wrote:
> On Mon, Apr 27, 2020 at 08:24:55AM +1000, Dave Chinner wrote:
> > On Sun, Apr 26, 2020 at 11:49:24PM +0200, Guoqing Jiang wrote:
> > > Since the new pair function is introduced, we can call them to clean the
> > > code in orangefs.
> > > 
> > > Cc: Mike Marshall <hubcap@omnibond.com>
> > > Cc: Martin Brandenburg <martin@omnibond.com>
> > > Cc: devel@lists.orangefs.org
> > > Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> > > ---
> > >  fs/orangefs/inode.c | 24 ++++++------------------
> > >  1 file changed, 6 insertions(+), 18 deletions(-)
> > > 
> > > diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
> > > index 12ae630fbed7..893099d36e20 100644
> > > --- a/fs/orangefs/inode.c
> > > +++ b/fs/orangefs/inode.c
> > > @@ -64,9 +64,7 @@ static int orangefs_writepage_locked(struct page *page,
> > >  	}
> > >  	if (wr) {
> > >  		kfree(wr);
> > > -		set_page_private(page, 0);
> > > -		ClearPagePrivate(page);
> > > -		put_page(page);
> > > +		clear_fs_page_private(page);
> > 
> > THis is a pre-existing potential use-after-free vector. The wr
> > pointer held in the page->private needs to be cleared from the page
> > before it is freed.
> 
> I'm not familar with orangefs. In my opinion, generally all temporary
> page->private access (r/w) should be properly protected by some locks,

... page->private pointers (there may be some other uses rather than
as references). sorry about that...

> most of time I think it could be at least page lock since .migratepage,
> .invalidatepage, .releasepage, .. (such paths) are already called with
> page locked (honestly I'm interested in this topic, please correct me
> if I'm wrong).
> 
> I agree that the suggested modification is more clear and easy to read.
> 
> Thanks,
> Gao Xiang
> 
> 

  reply	other threads:[~2020-04-27  3:29 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-26 21:49 [RFC PATCH 0/9] Introduce set/clear_fs_page_private to cleanup code Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 1/9] include/linux/pagemap.h: introduce set/clear_fs_page_private Guoqing Jiang
2020-04-27  5:52   ` Christoph Hellwig
2020-04-27  8:10     ` Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 2/9] md: remove __clear_page_buffers and use set/clear_fs_page_private Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 3/9] btrfs: " Guoqing Jiang
2020-04-26 22:20   ` Dave Chinner
2020-04-27  5:54     ` Christoph Hellwig
2020-04-27 12:27       ` David Sterba
2020-04-27  8:14     ` Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 4/9] fs/buffer.c: " Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 5/9] f2fs: " Guoqing Jiang
2020-04-27  2:22   ` Chao Yu
2020-04-27  8:10     ` Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 6/9] iomap: " Guoqing Jiang
2020-04-27  0:26   ` Matthew Wilcox
2020-04-27  5:55     ` Christoph Hellwig
2020-04-27  8:15       ` Guoqing Jiang
2020-04-27  8:15     ` Guoqing Jiang
2020-04-27  5:57   ` Christoph Hellwig
2020-04-27  8:12     ` Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 7/9] ntfs: replace attach_page_buffers with set_fs_page_private Guoqing Jiang
2020-04-26 21:49 ` [RFC PATCH 8/9] orangefs: use set/clear_fs_page_private Guoqing Jiang
2020-04-26 22:24   ` Dave Chinner
2020-04-27  0:12     ` Matthew Wilcox
2020-04-27  2:27       ` Dave Chinner
2020-04-27  8:18         ` Guoqing Jiang
2020-04-27  2:58     ` Gao Xiang
2020-04-27  3:27       ` Gao Xiang [this message]
2020-04-26 21:49 ` [RFC PATCH 9/9] buffer_head.h: remove attach_page_buffers Guoqing Jiang

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