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

[Manfred Spraul]

Ingo Molnar wrote:

> Exactly that happens.
>
> > I'm running with CONFIG_PAGE_DEBUG, i.e. unallocated pages are marked as 
> > non-present in the linear mapping.
> >    
>
> 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.
It is possible to use direct_copy_ instead of memcpy for fs==KERNEL_DS 
in mm/usercopy.c?

--
   Manfred

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/