Re: [patch] mm: nobootmem: fix sign extend problem in __free_pages_memory()
From: Yinghai Lu
Date: Tue May 08 2012 - 16:17:39 EST
On Mon, May 7, 2012 at 12:32 PM, Russ Anderson <rja@xxxxxxx> wrote:
> Systems with 8 TBytes of memory or greater can hit a problem
> where only the the first 8 TB of memory shows up. This is
> due to "int i" being smaller than "unsigned long start_aligned",
> causing the high bits to be dropped.
when you have 8T installed, you should get [0,2g), [4g, 8T+2g)
if you have more than that. [2g, 4g) could be added as ram together
with MMIO....
>
> The fix is to change i to unsigned long to match start_aligned
> and end_aligned.
>
> Thanks to Jack Steiner (steiner@xxxxxxx) for assistance tracking
> this down.
>
> Signed-off-by: Russ Anderson <rja@xxxxxxx>
>
> ---
> mm/nobootmem.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> Index: linux/mm/nobootmem.c
> ===================================================================
> --- linux.orig/mm/nobootmem.c 2012-05-05 08:39:39.470845187 -0500
> +++ linux/mm/nobootmem.c 2012-05-05 08:39:42.714784530 -0500
> @@ -82,8 +82,7 @@ void __init free_bootmem_late(unsigned l
>
> static void __init __free_pages_memory(unsigned long start, unsigned long end)
> {
> - int i;
> - unsigned long start_aligned, end_aligned;
> + unsigned long i, start_aligned, end_aligned;
> int order = ilog2(BITS_PER_LONG);
>
> start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1);
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
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