diff --git a/src/runtime/lock_futex.go b/src/runtime/lock_futex.go
index 29b7be0d8f..91467fdfae 100644
--- a/src/runtime/lock_futex.go
+++ b/src/runtime/lock_futex.go
@@ -238,8 +238,8 @@ func notetsleepg(n *note, ns int64) bool {
 	return ok
 }
 
-func beforeIdle(int64) bool {
-	return false
+func beforeIdle(int64) (*g, bool) {
+	return nil, false
 }
 
 func checkTimeouts() {}
diff --git a/src/runtime/lock_js.go b/src/runtime/lock_js.go
index 429ce63923..14bdc76842 100644
--- a/src/runtime/lock_js.go
+++ b/src/runtime/lock_js.go
@@ -173,7 +173,9 @@ var idleID int32
 // beforeIdle gets called by the scheduler if no goroutine is awake.
 // If we are not already handling an event, then we pause for an async event.
 // If an event handler returned, we resume it and it will pause the execution.
-func beforeIdle(delay int64) bool {
+// beforeIdle either returns the specific goroutine to schedule next or
+// indicates with otherReady that some goroutine became ready.
+func beforeIdle(delay int64) (gp *g, otherReady bool) {
 	if delay > 0 {
 		clearIdleID()
 		if delay < 1e6 {
@@ -190,15 +192,14 @@ func beforeIdle(delay int64) bool {
 
 	if len(events) == 0 {
 		go handleAsyncEvent()
-		return true
+		return nil, true
 	}
 
 	e := events[len(events)-1]
 	if e.returned {
-		goready(e.gp, 1)
-		return true
+		return e.gp, false
 	}
-	return false
+	return nil, false
 }
 
 func handleAsyncEvent() {
diff --git a/src/runtime/lock_sema.go b/src/runtime/lock_sema.go
index bf2584ac92..671e524e45 100644
--- a/src/runtime/lock_sema.go
+++ b/src/runtime/lock_sema.go
@@ -297,8 +297,8 @@ func notetsleepg(n *note, ns int64) bool {
 	return ok
 }
 
-func beforeIdle(int64) bool {
-	return false
+func beforeIdle(int64) (*g, bool) {
+	return nil, false
 }
 
 func checkTimeouts() {}
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index e5823dd804..766784c07e 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -2286,9 +2286,17 @@ stop:
 
 	// wasm only:
 	// If a callback returned and no other goroutine is awake,
-	// then pause execution until a callback was triggered.
-	if beforeIdle(delta) {
-		// At least one goroutine got woken.
+	// then wake event handler goroutine which pauses execution
+	// until a callback was triggered.
+	gp, otherReady := beforeIdle(delta)
+	if gp != nil {
+		casgstatus(gp, _Gwaiting, _Grunnable)
+		if trace.enabled {
+			traceGoUnpark(gp, 0)
+		}
+		return gp, false
+	}
+	if otherReady {
 		goto top
 	}
 
diff --git a/test/fixedbugs/issue38093.go b/test/fixedbugs/issue38093.go
new file mode 100644
index 0000000000..db92664a49
--- /dev/null
+++ b/test/fixedbugs/issue38093.go
@@ -0,0 +1,49 @@
+// +build js
+// run
+
+// Copyright 2020 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.
+
+// Test race condition between timers and wasm calls that led to memory corruption.
+
+package main
+
+import (
+	"os"
+	"syscall/js"
+	"time"
+)
+
+func main() {
+	ch1 := make(chan struct{})
+
+	go func() {
+		for {
+			time.Sleep(5 * time.Millisecond)
+			ch1 <- struct{}{}
+		}
+	}()
+	go func() {
+		for {
+			time.Sleep(8 * time.Millisecond)
+			ch1 <- struct{}{}
+		}
+	}()
+	go func() {
+		time.Sleep(2 * time.Second)
+		os.Exit(0)
+	}()
+
+	for range ch1 {
+		ch2 := make(chan struct{}, 1)
+		f := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+			ch2 <- struct{}{}
+			return nil
+		})
+		defer f.Release()
+		fn := js.Global().Get("Function").New("cb", "cb();")
+		fn.Invoke(f)
+		<-ch2
+	}
+}