From aeeda707ffdcd29efdec510ffe40061384b0dfdf Mon Sep 17 00:00:00 2001
From: Emil Hessman <c.emil.hessman@gmail.com>
Date: Mon, 6 Jan 2014 09:53:55 -0800
Subject: [PATCH] runtime: Fix panic when trying to stop CPU profiling with
 profiler turned off

Fixes #7063.

R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/47950043
---
 src/pkg/runtime/cpuprof.c       | 2 +-
 src/pkg/runtime/runtime_test.go | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/pkg/runtime/cpuprof.c b/src/pkg/runtime/cpuprof.c
index 1c34b9e6f6..040ffcd8c7 100644
--- a/src/pkg/runtime/cpuprof.c
+++ b/src/pkg/runtime/cpuprof.c
@@ -168,7 +168,7 @@ runtime·SetCPUProfileRate(intgo hz)
 		runtime·noteclear(&prof->wait);
 
 		runtime·setcpuprofilerate(tick, hz);
-	} else if(prof->on) {
+	} else if(prof != nil && prof->on) {
 		runtime·setcpuprofilerate(nil, 0);
 		prof->on = false;
 
diff --git a/src/pkg/runtime/runtime_test.go b/src/pkg/runtime/runtime_test.go
index f6b48ba3a6..c673275620 100644
--- a/src/pkg/runtime/runtime_test.go
+++ b/src/pkg/runtime/runtime_test.go
@@ -126,3 +126,8 @@ func TestRuntimeGogoBytes(t *testing.T) {
 
 	t.Fatalf("go tool nm did not report size for runtime.gogo")
 }
+
+// golang.org/issue/7063
+func TestStopCPUProfilingWithProfilerOff(t *testing.T) {
+	SetCPUProfileRate(0)
+}