From: Dave Olien <dmo@osdl.org>
To: akpm@osdl.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 2.6.0-test4-mm2 drivers/char.c ---> drivers/char/raw.c
Date: Thu, 28 Aug 2003 16:22:29 -0700 [thread overview]
Message-ID: <20030828232228.GA7242@osdl.org> (raw)
In-Reply-To: <20030828231853.GA7192@osdl.org>
Mistake in subject line... should refer to drivers/char/raw.c
On Thu, Aug 28, 2003 at 04:18:53PM -0700, Dave Olien wrote:
>
> The raw.c character device Oopses dereferencing a NULL pointer in bd_claim()
> This problem occurred after bd_claim() in block_dev.c was modified to "claim
> the whole device when a partition is claimed".
>
> raw_open() made the mistake of calling bd_claim BEFORE calling
> blkdev_get(). At that time, the bdev->bd_contains field. has't been
> initialized yet. Switching the order allows blkdev_get() to initialize
> those fields before calling bd_claim().
>
> Also fixed up some error return paths:
>
> igrab() should never fail under these circumstances since the caller
> already has a reference to that inode through the bdev at that time.
>
> In the event of blkdev_get() failure or set_blocksize() failure, not
> all the work to unwind from the error was done.
>
> --- linux-2.6.0-test4-mm2_original/drivers/char/raw.c 2003-08-28 13:16:03.000000000 -0700
> +++ linux-2.6.0-test4-mm2_raw/drivers/char/raw.c 2003-08-28 14:07:44.000000000 -0700
> @@ -60,25 +60,25 @@
> bdev = raw_devices[minor].binding;
> err = -ENODEV;
> if (bdev) {
> - err = bd_claim(bdev, raw_open);
> + err = blkdev_get(bdev, filp->f_mode, 0, BDEV_RAW);
> if (err)
> goto out;
> - err = -ENODEV;
> - if (!igrab(bdev->bd_inode))
> + igrab(bdev->bd_inode);
> + err = bd_claim(bdev, raw_open);
> + if (err) {
> + blkdev_put(bdev, BDEV_RAW);
> goto out;
> - err = blkdev_get(bdev, filp->f_mode, 0, BDEV_RAW);
> + }
> + err = set_blocksize(bdev, bdev_hardsect_size(bdev));
> if (err) {
> bd_release(bdev);
> + blkdev_put(bdev, BDEV_RAW);
> goto out;
> - } else {
> - err = set_blocksize(bdev, bdev_hardsect_size(bdev));
> - if (err == 0) {
> - filp->f_flags |= O_DIRECT;
> - if (++raw_devices[minor].inuse == 1)
> - filp->f_dentry->d_inode->i_mapping =
> - bdev->bd_inode->i_mapping;
> - }
> }
> + filp->f_flags |= O_DIRECT;
> + if (++raw_devices[minor].inuse == 1)
> + filp->f_dentry->d_inode->i_mapping =
> + bdev->bd_inode->i_mapping;
> }
> filp->private_data = bdev;
> out:
prev parent reply other threads:[~2003-08-28 23:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-28 23:18 [PATCH] 2.6.0-test4-mm2 drivers/char.c Oops on open() Dave Olien
2003-08-28 23:22 ` Dave Olien [this message]
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