[PATCH] x86_64: Fix partial page check to ensure unusable memory is not being marked usable.

[PATCH] x86_64: Fix partial page check to ensure unusable memory is not being marked usable.

[Aaron Durbin]

Fix partial page check in e820_register_active_regions to ensure
partial pages are
not being marked as active in the memory pool.

Signed-off-by: Aaron Durbin <adurbin@google.com>

---
This was causing a machine to reboot w/ an area in the e820 that was less
than the page size because the upper address was being use to mark a hole as
active in the memory pool.

 arch/x86_64/kernel/e820.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
index a75c829..855b561 100644
--- a/arch/x86_64/kernel/e820.c
+++ b/arch/x86_64/kernel/e820.c
@@ -278,7 +278,7 @@ e820_register_active_regions(int nid, un
 								>> PAGE_SHIFT;

 		/* Skip map entries smaller than a page */
-		if (ei_startpfn > ei_endpfn)
+		if (ei_startpfn >= ei_endpfn)
 			continue;

 		/* Check if end_pfn_map should be updated */
-- 
1.4.2.GIT

Re: [PATCH] x86_64: Fix partial page check to ensure unusable memory is not being marked usable.

[Andi Kleen]

On Thursday 09 November 2006 22:27, Aaron Durbin wrote:
> Fix partial page check in e820_register_active_regions to ensure
> partial pages are
> not being marked as active in the memory pool.

Added thanks.

Critical fix for .19 i guess

-Andi

Re: [PATCH] x86_64: Fix partial page check to ensure unusable memory is not being marked usable.

[Mel Gorman]

On Thu, 9 Nov 2006, Aaron Durbin wrote:

> Fix partial page check in e820_register_active_regions to ensure
> partial pages are
> not being marked as active in the memory pool.
>
> Signed-off-by: Aaron Durbin <adurbin@google.com>
>

Acked-by: Mel Gorman <mel@csn.ul.ie.ie>

This bug is in 2.6.19-rc5 and the patch will be needed for 2.6.19.

Thanks Aaron.

> ---
> This was causing a machine to reboot w/ an area in the e820 that was less
> than the page size because the upper address was being use to mark a hole as
> active in the memory pool.
>
> arch/x86_64/kernel/e820.c |    2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
> index a75c829..855b561 100644
> --- a/arch/x86_64/kernel/e820.c
> +++ b/arch/x86_64/kernel/e820.c
> @@ -278,7 +278,7 @@ e820_register_active_regions(int nid, un
> 								>> 
> PAGE_SHIFT;
>
> 		/* Skip map entries smaller than a page */
> -		if (ei_startpfn > ei_endpfn)
> +		if (ei_startpfn >= ei_endpfn)
> 			continue;
>
> 		/* Check if end_pfn_map should be updated */
> -- 
> 1.4.2.GIT
>

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab