Date: Thu, 1 Feb 2007 14:26:48 -0800
From: Andrew Morton <akpm@osdl.org>
To: TJ <linux@tjworld.net>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>, Neil Brown <neilb@suse.de>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] filesystem: Disk Errors at boot-time caused by
 probe of partitions
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On Wed, 31 Jan 2007 23:50:39 +0000
TJ <linux@tjworld.net> wrote:

> +		if (!insane && is_extended_partition(p)) { /* check the extended partition */
> +			data = read_dev_sector(bdev, START_SECT(p)*sector_size, &sect); /* fetch sector from cache */
> +			if (data) {
> +				if (msdos_magic_present(data + 510)) { /* check for signature */
> +					ext = (struct partition *) (data + 0x1be);
> +					ret = check_sane_values(ext, bdev); /* recursive call */

The recursion is a concern.  Is there any way in which a cunningly-crafted
device can cause sufficiently deep recursion to crash the kernel?

Also, from reading the replies I think we'd like to see some more
explanation of why this is necessary: are you really really sure that those
disks were incorrectly handling illegal sector numbers?  Knowing the IBM
and Maxtor model numbers might be useful.

I assume you were using a driver in drivers/ide/?  Perhaps this is really
an IDE-layer bug.
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