linux-kernel - [patch] mm: nobootmem: fix sign extend problem in __free_pages

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Date:	Mon, 7 May 2012 14:32:03 -0500
From:	Russ Anderson <rja@....com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Yinghai Lu <yinghai@...nel.org>,
	David Miller <davem@...emloft.net>
Cc:	Russ Anderson <rja@....com>
Subject: [patch] mm: nobootmem: fix sign extend problem in __free_pages_memory()

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.

The fix is to change i to unsigned long to match start_aligned
and end_aligned.

Thanks to Jack Steiner (steiner@....com) for assistance tracking
this down.

Signed-off-by: Russ Anderson <rja@....com>

---
 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);
-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@....com
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