src/runtime/time.go | 6 ++++++

diff --git a/src/runtime/time.go b/src/runtime/time.go
index fdb5066b24f31718d7db566c4ac5821efbf911b6..ec3eae9ccad4010fcd79afc8e71b46825844ab3d 100644
--- a/src/runtime/time.go
+++ b/src/runtime/time.go
@@ -594,8 +594,14 @@ 	loop:
 		for {
 			switch s := atomic.Load(&t.status); s {
 			case timerWaiting:
+				if !atomic.Cas(&t.status, s, timerMoving) {
+					continue
+				}
 				t.pp = 0
 				doaddtimer(pp, t)
+				if !atomic.Cas(&t.status, timerMoving, timerWaiting) {
+					badTimer()
+				}
 				break loop
 			case timerModifiedEarlier, timerModifiedLater:
 				if !atomic.Cas(&t.status, s, timerMoving) {