[PATCH] rbtree: Add some necessary condition checks

[zwu.kernel@gmail.com]

From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
 include/linux/rbtree_augmented.h | 3 ++-
 lib/rbtree.c                     | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/rbtree_augmented.h b/include/linux/rbtree_augmented.h
index fea49b5..7d19770 100644
--- a/include/linux/rbtree_augmented.h
+++ b/include/linux/rbtree_augmented.h
@@ -199,7 +199,8 @@ __rb_erase_augmented(struct rb_node *node, struct rb_root *root,
 		}
 
 		successor->rb_left = tmp = node->rb_left;
-		rb_set_parent(tmp, successor);
+		if (tmp)
+			rb_set_parent(tmp, successor);
 
 		pc = node->__rb_parent_color;
 		tmp = __rb_parent(pc);
diff --git a/lib/rbtree.c b/lib/rbtree.c
index c0e31fe..329f2bc 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -226,7 +226,8 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root,
 				 */
 				parent->rb_right = tmp1 = sibling->rb_left;
 				sibling->rb_left = parent;
-				rb_set_parent_color(tmp1, parent, RB_BLACK);
+				if (tmp1)
+					rb_set_parent_color(tmp1, parent, RB_BLACK);
 				__rb_rotate_set_parents(parent, sibling, root,
 							RB_RED);
 				augment_rotate(parent, sibling);
-- 
1.7.11.7