Index: sys/sys/tree.h
===================================================================
--- sys/sys/tree.h
+++ sys/sys/tree.h
@@ -340,6 +340,7 @@
 #define RB_RED_MASK			((__uintptr_t)3)
 #define RB_FLIP_LEFT(elm, field)	(RB_BITS(elm, field) ^= RB_RED_L)
 #define RB_FLIP_RIGHT(elm, field)	(RB_BITS(elm, field) ^= RB_RED_R)
+#define RB_FLIP_ALL(elm, field)		(RB_BITS(elm, field) ^= RB_RED_MASK)
 #define RB_RED_LEFT(elm, field)		((RB_BITS(elm, field) & RB_RED_L) != 0)
 #define RB_RED_RIGHT(elm, field)	((RB_BITS(elm, field) & RB_RED_R) != 0)
 #define RB_PARENT(elm, field)		((__typeof(RB_UP(elm, field)))	\
@@ -348,8 +349,8 @@
 #define RB_EMPTY(head)			(RB_ROOT(head) == NULL)
 
 #define RB_SET_PARENT(dst, src, field) do {				\
-	RB_BITS(dst, field) &= RB_RED_MASK;				\
-	RB_BITS(dst, field) |= (__uintptr_t)src;			\
+	RB_BITS(dst, field) = (__uintptr_t)src |			\
+		(RB_BITS(dst, field) & RB_RED_MASK);			\
 } while (/*CONSTCOND*/ 0)
 
 #define RB_SET(elm, parent, field) do {					\
@@ -487,13 +488,14 @@
 				continue;				\
 			}						\
 			if (!RB_RED_RIGHT(elm, field)) {		\
-				RB_FLIP_LEFT(elm, field);		\
 				/* coverity[uninit_use] */		\
 				RB_ROTATE_LEFT(head, elm, child, field);\
-				if (RB_RED_LEFT(child, field))		\
-					RB_FLIP_RIGHT(elm, field);	\
-				else if (RB_RED_RIGHT(child, field))	\
+				if (RB_RED_RIGHT(child, field))		\
 					RB_FLIP_LEFT(parent, field);	\
+				if (RB_RED_LEFT(child, field))		\
+					RB_FLIP_ALL(elm, field);	\
+				else					\
+					RB_FLIP_LEFT(elm, field);	\
 				elm = child;				\
 			}						\
 			RB_ROTATE_RIGHT(head, parent, elm, field);	\
@@ -509,13 +511,14 @@
 				continue;				\
 			}						\
 			if (!RB_RED_LEFT(elm, field)) {			\
-				RB_FLIP_RIGHT(elm, field);		\
 				/* coverity[uninit_use] */		\
 				RB_ROTATE_RIGHT(head, elm, child, field);\
-				if (RB_RED_RIGHT(child, field))		\
-					RB_FLIP_LEFT(elm, field);	\
-				else if (RB_RED_LEFT(child, field))	\
+				if (RB_RED_LEFT(child, field))		\
 					RB_FLIP_RIGHT(parent, field);	\
+				if (RB_RED_RIGHT(child, field))		\
+					RB_FLIP_ALL(elm, field);	\
+				else					\
+					RB_FLIP_RIGHT(elm, field);	\
 				elm = child;				\
 			}						\
 			RB_ROTATE_LEFT(head, parent, elm, field);	\