On Mon, May 16, 2005 at 02:13:02AM -0700, Andrew Morton wrote:
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc4/2.6.12-rc4-mm2/
> - davem has set up a mm-commits mailing list so people can review things
>   which are added to or removed from the -mm tree.  Do
> 	echo subscribe mm-commits | mail majordomo@vger.kernel.org
> - x86_64 architecture update from Andi.
> - Everything up to and including `spurious-interrupt-fix.patch' is planned
>   for 2.6.12 merging.  Plus a few other things in there.
> - Another DVB subsystem update

try_to_unmap_cluster() does:
        for (pte = pte_offset_map(pmd, address);
                        address < end; pte++, address += PAGE_SIZE) {
		...
	}

	pte_unmap(pte);

It may take a little staring to notice, but pte can actually fall off
the end of the pte page in this iteration, which makes life difficult
for kmap_atomic() and the users not expecting it to BUG(). Of course,
we're somewhat lucky in that arithmetic elsewhere in the function
guarantees that at least one iteration is made, lest this force larger
rearrangements to be made. This issue and patch also apply to non-mm
mainline and with trivial adjustments, at least two related kernels.

Discovered during internal testing at Oracle. Sample BUG() message
included along with patch as a MIME attachment.

Signed-off-by: William Irwin <wli@holomorphy.com>


-- wli