1 files changed, 63 insertions, 20 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 95250d7c8d9..5f91a07c4ea 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -447,7 +447,7 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
  *	of @bm->cur_zone_bm are updated.
  */
 
-static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
+static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
 				void **addr, unsigned int *bit_nr)
 {
 	struct zone_bitmap *zone_bm;
@@ -461,7 +461,8 @@ static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
 		while (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
 			zone_bm = zone_bm->next;
 
-			BUG_ON(!zone_bm);
+			if (!zone_bm)
+				return -EFAULT;
 		}
 		bm->cur.zone_bm = zone_bm;
 	}
@@ -479,23 +480,40 @@ static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
 	pfn -= bb->start_pfn;
 	*bit_nr = pfn % BM_BITS_PER_CHUNK;
 	*addr = bb->data + pfn / BM_BITS_PER_CHUNK;
+	return 0;
 }
 
 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
 {
 	void *addr;
 	unsigned int bit;
+	int error;
 
-	memory_bm_find_bit(bm, pfn, &addr, &bit);
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
 	set_bit(bit, addr);
 }
 
+static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+	int error;
+
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	if (!error)
+		set_bit(bit, addr);
+	return error;
+}
+
 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
 {
 	void *addr;
 	unsigned int bit;
+	int error;
 
-	memory_bm_find_bit(bm, pfn, &addr, &bit);
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
 	clear_bit(bit, addr);
 }
 
@@ -503,8 +521,10 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
 {
 	void *addr;
 	unsigned int bit;
+	int error;
 
-	memory_bm_find_bit(bm, pfn, &addr, &bit);
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
 	return test_bit(bit, addr);
 }
 
@@ -709,8 +729,15 @@ static void mark_nosave_pages(struct memory_bitmap *bm)
 				region->end_pfn << PAGE_SHIFT);
 
 		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
-			if (pfn_valid(pfn))
-				memory_bm_set_bit(bm, pfn);
+			if (pfn_valid(pfn)) {
+				/*
+				 * It is safe to ignore the result of
+				 * mem_bm_set_bit_check() here, since we won't
+				 * touch the PFNs for which the error is
+				 * returned anyway.
+				 */
+				mem_bm_set_bit_check(bm, pfn);
+			}
 	}
 }
 
@@ -875,8 +902,8 @@ static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
 #endif /* CONFIG_HIGHMEM */
 
 /**
- *	saveable - Determine whether a non-highmem page should be included in
- *	the suspend image.
+ *	saveable_page - Determine whether a non-highmem page should be included
+ *	in the suspend image.
  *
  *	We should save the page if it isn't Nosave, and is not in the range
  *	of pages statically defined as 'unsaveable', and it isn't a part of
@@ -897,7 +924,8 @@ static struct page *saveable_page(unsigned long pfn)
 	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
 		return NULL;
 
-	if (PageReserved(page) && pfn_is_nosave(pfn))
+	if (PageReserved(page)
+	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
 		return NULL;
 
 	return page;
@@ -938,6 +966,25 @@ static inline void do_copy_page(long *dst, long *src)
 		*dst++ = *src++;
 }
 
+
+/**
+ *	safe_copy_page - check if the page we are going to copy is marked as
+ *		present in the kernel page tables (this always is the case if
+ *		CONFIG_DEBUG_PAGEALLOC is not set and in that case
+ *		kernel_page_present() always returns 'true').
+ */
+static void safe_copy_page(void *dst, struct page *s_page)
+{
+	if (kernel_page_present(s_page)) {
+		do_copy_page(dst, page_address(s_page));
+	} else {
+		kernel_map_pages(s_page, 1, 1);
+		do_copy_page(dst, page_address(s_page));
+		kernel_map_pages(s_page, 1, 0);
+	}
+}
+
+
 #ifdef CONFIG_HIGHMEM
 static inline struct page *
 page_is_saveable(struct zone *zone, unsigned long pfn)
@@ -946,8 +993,7 @@ page_is_saveable(struct zone *zone, unsigned long pfn)
 			saveable_highmem_page(pfn) : saveable_page(pfn);
 }
 
-static inline void
-copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 {
 	struct page *s_page, *d_page;
 	void *src, *dst;
@@ -961,29 +1007,26 @@ copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 		kunmap_atomic(src, KM_USER0);
 		kunmap_atomic(dst, KM_USER1);
 	} else {
-		src = page_address(s_page);
 		if (PageHighMem(d_page)) {
 			/* Page pointed to by src may contain some kernel
 			 * data modified by kmap_atomic()
 			 */
-			do_copy_page(buffer, src);
+			safe_copy_page(buffer, s_page);
 			dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
 			memcpy(dst, buffer, PAGE_SIZE);
 			kunmap_atomic(dst, KM_USER0);
 		} else {
-			dst = page_address(d_page);
-			do_copy_page(dst, src);
+			safe_copy_page(page_address(d_page), s_page);
 		}
 	}
 }
 #else
 #define page_is_saveable(zone, pfn)	saveable_page(pfn)
 
-static inline void
-copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 {
-	do_copy_page(page_address(pfn_to_page(dst_pfn)),
-			page_address(pfn_to_page(src_pfn)));
+	safe_copy_page(page_address(pfn_to_page(dst_pfn)),
+				pfn_to_page(src_pfn));
 }
 #endif /* CONFIG_HIGHMEM */