1 files changed, 28 insertions, 4 deletions
diff --git a/libgo/go/runtime/mstkbar.go b/libgo/go/runtime/mstkbar.go
index 016625ae925..1bf9d573b70 100644
--- a/libgo/go/runtime/mstkbar.go
+++ b/libgo/go/runtime/mstkbar.go
@@ -214,14 +214,15 @@ func gcInstallStackBarrier(gp *g, frame *stkframe) bool {
 }
 
 // gcRemoveStackBarriers removes all stack barriers installed in gp's stack.
+//
+// gp's stack barriers must be locked.
+//
 //go:nowritebarrier
 func gcRemoveStackBarriers(gp *g) {
 	if debugStackBarrier && gp.stkbarPos != 0 {
 		print("hit ", gp.stkbarPos, " stack barriers, goid=", gp.goid, "\n")
 	}
 
-	gcLockStackBarriers(gp)
-
 	// Remove stack barriers that we didn't hit.
 	for _, stkbar := range gp.stkbar[gp.stkbarPos:] {
 		gcRemoveStackBarrier(gp, stkbar)
@@ -231,8 +232,6 @@ func gcRemoveStackBarriers(gp *g) {
 	// adjust them.
 	gp.stkbarPos = 0
 	gp.stkbar = gp.stkbar[:0]
-
-	gcUnlockStackBarriers(gp)
 }
 
 // gcRemoveStackBarrier removes a single stack barrier. It is the
@@ -258,6 +257,31 @@ func gcRemoveStackBarrier(gp *g, stkbar stkbar) {
 	*lrPtr = sys.Uintreg(stkbar.savedLRVal)
 }
 
+// gcTryRemoveAllStackBarriers tries to remove stack barriers from all
+// Gs in gps. It is best-effort and efficient. If it can't remove
+// barriers from a G immediately, it will simply skip it.
+func gcTryRemoveAllStackBarriers(gps []*g) {
+	for _, gp := range gps {
+	retry:
+		for {
+			switch s := readgstatus(gp); s {
+			default:
+				break retry
+
+			case _Grunnable, _Gsyscall, _Gwaiting:
+				if !castogscanstatus(gp, s, s|_Gscan) {
+					continue
+				}
+				gcLockStackBarriers(gp)
+				gcRemoveStackBarriers(gp)
+				gcUnlockStackBarriers(gp)
+				restartg(gp)
+				break retry
+			}
+		}
+	}
+}
+
 // gcPrintStkbars prints the stack barriers of gp for debugging. It
 // places a "@@@" marker at gp.stkbarPos. If marker >= 0, it will also
 // place a "==>" marker before the marker'th entry.