From 7c5371c403abb29f01bc6cff6c5096abdf2dc524 Mon Sep 17 00:00:00 2001
From: Yinghai Lu <yinghai@kernel.org>
Date: Wed, 1 Jul 2009 12:32:18 -0700
Subject: x86: add boundary check for 32bit res before expand e820 resource to
 alignment

fix hang with HIGHMEM_64G and 32bit resource.  According to hpa and
Linus, use (resource_size_t)-1 to fend off big ranges.

Analyzed by hpa

Reported-and-tested-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 7271fa3..c4ca89d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1383,6 +1383,8 @@ static unsigned long ram_alignment(resource_size_t pos)
 	return 32*1024*1024;
 }
 
+#define MAX_RESOURCE_SIZE ((resource_size_t)-1)
+
 void __init e820_reserve_resources_late(void)
 {
 	int i;
@@ -1400,17 +1402,19 @@ void __init e820_reserve_resources_late(void)
 	 * avoid stolen RAM:
 	 */
 	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *entry = &e820_saved.map[i];
-		resource_size_t start, end;
+		struct e820entry *entry = &e820.map[i];
+		u64 start, end;
 
 		if (entry->type != E820_RAM)
 			continue;
 		start = entry->addr + entry->size;
-		end = round_up(start, ram_alignment(start));
-		if (start == end)
+		end = round_up(start, ram_alignment(start)) - 1;
+		if (end > MAX_RESOURCE_SIZE)
+			end = MAX_RESOURCE_SIZE;
+		if (start >= end)
 			continue;
-		reserve_region_with_split(&iomem_resource, start,
-						  end - 1, "RAM buffer");
+		reserve_region_with_split(&iomem_resource, start, end,
+					  "RAM buffer");
 	}
 }
 
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