Re: 4GB+DEBUG_PAGEALLOC oopses with 2.6.0-test3-mm1

From: Ingo Molnar
Date: Mon Aug 11 2003 - 12:37:12 EST



On Mon, 11 Aug 2003, Manfred Spraul wrote:

> > this is not a bug technically, unless the mount options are in the
> > last linearly mapped page. It is a bug to copy those unallocated
> > bytes, but they do not get to relied upon. Note that the non-4G code
> > copies them just as much.
>
> Or unless there are holes in the memory map, or unless pages were
> unmapped from the kernel linear mapping for GART.
> IMHO the currect code is unacceptable.

IMHO the mount-options API is quite unclean - since when do we guarantee
-EFAULT semantics?

> It is possible to use direct_copy_ instead of memcpy for fs==KERNEL_DS
> in mm/usercopy.c?

yes. But i still think we should fix the API too.

Ingo
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