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From: Christoph Hellwig <hch@infradead.org>
To: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: linux-kernel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>,
	Matthew Wilcox <willy@linux.intel.com>,
	linux-fsdevel@vger.kernel.org, linux-nvdimm@ml01.01.org
Subject: Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences
Date: Thu, 28 Jan 2016 13:38:58 -0800	[thread overview]
Message-ID: <20160128213858.GA29114@infradead.org> (raw)
In-Reply-To: <1454009704-25959-2-git-send-email-ross.zwisler@linux.intel.com>

On Thu, Jan 28, 2016 at 12:35:04PM -0700, Ross Zwisler wrote:
> There are a number of places in dax.c that look up the struct block_device
> associated with an inode.  Previously this was done by just using
> inode->i_sb->s_bdev.  This is correct for inodes that exist within the
> filesystems supported by DAX (ext2, ext4 & XFS), but when running DAX
> against raw block devices this value is NULL.  This causes NULL pointer
> dereferences when these block_device pointers are used.

It's also wrong for an XFS file system with a RT device..

> +#define DAX_BDEV(inode) (S_ISBLK(inode->i_mode) ? I_BDEV(inode) \
> +				: inode->i_sb->s_bdev)

.. but this isn't going to fix it.  You must use a bdev returned by
get_blocks or a similar file system method.

  parent reply	other threads:[~2016-01-28 21:39 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28 19:35 [PATCH 1/2] block: fix pfn_mkwrite() DAX fault handler Ross Zwisler
2016-01-28 19:35 ` [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler
2016-01-28 20:21   ` Dan Williams
2016-01-28 21:38   ` Christoph Hellwig [this message]
2016-01-29 18:28     ` Ross Zwisler
2016-01-29 23:34       ` Ross Zwisler
2016-01-30  0:18         ` Dan Williams
2016-01-31 22:44         ` Dave Chinner
2016-01-30  5:28       ` Matthew Wilcox
2016-01-30  6:01         ` Dan Williams
2016-01-30  7:08           ` Jared Hulbert
2016-01-31  2:32           ` Matthew Wilcox
2016-01-31  6:12             ` Ross Zwisler
2016-01-31 10:55               ` Matthew Wilcox
2016-01-31 16:38                 ` Dan Williams
2016-01-31 18:07                   ` Matthew Wilcox
2016-01-31 18:18                     ` Dan Williams
2016-01-31 18:27                       ` Matthew Wilcox
2016-01-31 18:50                         ` Dan Williams
2016-01-31 19:51                     ` Dan Williams
2016-02-01 13:44             ` Matthew Wilcox
2016-02-01 14:51         ` Jan Kara
2016-02-01 20:49           ` Matthew Wilcox
2016-02-01 21:47           ` Dave Chinner
2016-02-02  6:06             ` Jared Hulbert
2016-02-02  6:46               ` Dan Williams
2016-02-02  8:05                 ` Jared Hulbert
2016-02-02 16:51                   ` Dan Williams
2016-02-02 21:46                     ` Jared Hulbert
2016-02-03  0:34                       ` Matthew Wilcox
2016-02-03  1:21                         ` Jared Hulbert
2016-02-02 11:17             ` Jan Kara
2016-02-02 16:33               ` Dan Williams
2016-02-02 16:46                 ` Jan Kara
2016-02-02 17:10                   ` Dan Williams
2016-02-02 17:34                     ` Ross Zwisler
2016-02-02 17:46                       ` Dan Williams
2016-02-02 17:47                         ` Dan Williams
2016-02-02 18:24                           ` Ross Zwisler
2016-02-02 18:46                         ` Matthew Wilcox
2016-02-02 18:59                           ` Dan Williams
2016-02-02 20:14                             ` Matthew Wilcox
2016-02-03 11:09                           ` Jan Kara
2016-02-03 10:46                       ` Jan Kara
2016-02-03 20:13                         ` Ross Zwisler
2016-02-04  9:15                           ` Jan Kara
2016-02-04 23:38                             ` Ross Zwisler
2016-02-06 23:15                             ` Dave Chinner
2016-02-07  5:27                               ` Ross Zwisler
2016-02-04 19:56                         ` Ross Zwisler
2016-02-04 20:29                           ` Jan Kara
2016-02-04 22:19                             ` Ross Zwisler
2016-02-05 22:25                             ` Ross Zwisler
2016-02-06 23:40                               ` Dave Chinner
2016-02-07  6:43                                 ` Ross Zwisler
2016-02-08 13:48                                   ` Jan Kara
2016-02-07  8:38                               ` Christoph Hellwig
2016-02-08 15:55                                 ` Ross Zwisler
2016-02-02 18:41               ` Ross Zwisler
2016-02-02 18:53                 ` Ross Zwisler
2016-02-02  0:02     ` Ross Zwisler
2016-02-02  7:10       ` Dave Chinner
2016-02-02 10:34       ` Jan Kara

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