Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h
+++ linux-2.6/include/linux/mm.h
@@ -293,7 +293,6 @@ struct page {
  */
 static inline int put_page_testzero(struct page *page)
 {
-	BUG_ON(atomic_read(&page->_count) == 0);
 	return atomic_dec_and_test(&page->_count);
 }
 
@@ -313,7 +312,6 @@ static inline void set_page_count(struct
 
 static inline void __put_page(struct page *page)
 {
-	BUG_ON(atomic_read(&page->_count) == 0);
 	atomic_dec(&page->_count);
 }
 
@@ -349,7 +347,6 @@ static inline void get_page(struct page 
 {
 	if (unlikely(PageCompound(page)))
 		page = (struct page *)page_private(page);
-	BUG_ON(atomic_read(&page->_count) == 0);
 	atomic_inc(&page->_count);
 }
 
@@ -364,13 +361,11 @@ static inline int page_count(struct page
 
 static inline void get_page(struct page *page)
 {
-	BUG_ON(atomic_read(&page->_count) == 0);
 	atomic_inc(&page->_count);
 }
 
 static inline void put_page(struct page *page)
 {
-	BUG_ON(atomic_read(&page->_count) == 0);
 	if (put_page_testzero(page))
 		__page_cache_release(page);
 }
Index: linux-2.6/mm/swap.c
===================================================================
--- linux-2.6.orig/mm/swap.c
+++ linux-2.6/mm/swap.c
@@ -40,7 +40,6 @@ void put_page(struct page *page)
 {
 	if (unlikely(PageCompound(page))) {
 		page = (struct page *)page_private(page);
-		BUG_ON(page_count(page) == 0);
 		if (put_page_testzero(page)) {
 			void (*dtor)(struct page *page);
 
@@ -49,7 +48,6 @@ void put_page(struct page *page)
 		}
 		return;
 	}
-	BUG_ON(page_count(page) == 0);
 	if (put_page_testzero(page))
 		__page_cache_release(page);
 }
Index: linux-2.6/include/linux/pagemap.h
===================================================================
--- linux-2.6.orig/include/linux/pagemap.h
+++ linux-2.6/include/linux/pagemap.h
@@ -60,10 +60,16 @@ static inline struct page *page_cache_ge
 		return NULL;
 
 #ifndef CONFIG_SMP
-	BUG_ON(page_count(page) == 0);
+	/*
+	 * Preempt must be disabled here - we rely on rcu_read_lock doing
+	 * this for us.
+	 *
+	 * Pagecache won't be truncated from interrupt context, so if we have
+	 * found a page in the radix tree here, we have pinned its refcount by
+	 * disabling preempt, and hence no need for the "speculative get" that
+	 * SMP requires.
+	 */
 	atomic_inc(&page->_count);
-	BUG_ON(page != *pagep);
-	BUG_ON(PageCompound(page) && (struct page *)page_private(page) != page);
 	return page;
 #else
 
@@ -105,8 +111,6 @@ static inline struct page *page_cache_ge
 	if (unlikely(page != *pagep)) /* page no longer at *pagep? */
 		goto bad_page;
 
-	BUG_ON(PageCompound(page) && (struct page *)page_private(page) != page);
-
 	return page;
 
 bad_page:
@@ -114,7 +118,6 @@ bad_page:
 	put_page(page);
 	return NULL;
 #endif
-
 }
 
 static inline struct page *page_cache_alloc(struct address_space *x)