diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index d5acbee..dcdc7be 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -681,9 +681,6 @@
 		dumpgstatus(gp)
 		throw("casfrom_Gscanstatus: gp->status is not in scan state")
 	}
-	if newval == _Grunning {
-		gp.gcscanvalid = false
-	}
 }
 
 // This will return false if the gp is not in the expected status and the cas fails.
diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index dcb1b06..c4b1fb8 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -1016,6 +1016,7 @@
 			gp.preemptscan = false
 			gp.preempt = false
 			casfrom_Gscanstatus(gp, _Gscanwaiting, _Gwaiting)
+			// This clears gcscanvalid.
 			casgstatus(gp, _Gwaiting, _Grunning)
 			gp.stackguard0 = gp.stack.lo + _StackGuard
 			gogo(&gp.sched) // never return