diff --git a/src/runtime/iface.go b/src/runtime/iface.go
index 246b63b897..bb4eccc9bd 100644
--- a/src/runtime/iface.go
+++ b/src/runtime/iface.go
@@ -195,6 +195,8 @@ func (m *itab) init() string {
 	nt := int(x.mcount)
 	xmhdr := (*[1 << 16]method)(add(unsafe.Pointer(x), uintptr(x.moff)))[:nt:nt]
 	j := 0
+	methods := (*[1 << 16]unsafe.Pointer)(unsafe.Pointer(&m.fun[0]))[:ni:ni]
+	var fun0 unsafe.Pointer
 imethods:
 	for k := 0; k < ni; k++ {
 		i := &inter.mhdr[k]
@@ -216,7 +218,11 @@ imethods:
 				if tname.isExported() || pkgPath == ipkg {
 					if m != nil {
 						ifn := typ.textOff(t.ifn)
-						*(*unsafe.Pointer)(add(unsafe.Pointer(&m.fun[0]), uintptr(k)*sys.PtrSize)) = ifn
+						if k == 0 {
+							fun0 = ifn // we'll set m.fun[0] at the end
+						} else {
+							methods[k] = ifn
+						}
 					}
 					continue imethods
 				}
@@ -226,6 +232,7 @@ imethods:
 		m.fun[0] = 0
 		return iname
 	}
+	m.fun[0] = uintptr(fun0)
 	m.hash = typ.hash
 	return ""
 }
diff --git a/test/fixedbugs/issue31419.go b/test/fixedbugs/issue31419.go
new file mode 100644
index 0000000000..233111ae14
--- /dev/null
+++ b/test/fixedbugs/issue31419.go
@@ -0,0 +1,58 @@
+// run
+
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 31419: race in getitab when two goroutines try
+// to do the same failed interface conversion.
+
+package main
+
+type T int
+
+func (t T) M() {}
+
+type I interface {
+	M()
+	M2()
+}
+
+var t T
+var e interface{} = &t
+var ok = false
+var ch = make(chan int)
+
+func main() {
+	_, ok = e.(I) // populate itab cache with a false result
+
+	go f() // get itab in a loop
+
+	var i I
+	for k := 0; k < 10000; k++ {
+		i, ok = e.(I) // read the cached itab
+		if ok {
+			println("iteration", k, "i =", i, "&t =", &t)
+			panic("conversion succeeded")
+		}
+	}
+	<-ch
+}
+
+func f() {
+	for i := 0; i < 10000; i++ {
+		f1()
+	}
+	ch <- 1
+}
+
+func f1() {
+	defer func() {
+		err := recover()
+		if err == nil {
+			panic("did not panic")
+		}
+	}()
+	i := e.(I) // triggers itab.init, for getting the panic string
+	_ = i
+}