[dev.garbage] all: merge dev.cc (493ad916c3b1) into dev.garbage

TBR=austin
CC=golang-codereviews
https://codereview.appspot.com/179290043

1 files changed, 90 insertions, 0 deletions

diff --git a/test/fixedbugs/issue9110.go b/test/fixedbugs/issue9110.go
new file mode 100644
index 000000000..729463305
--- /dev/null
+++ b/test/fixedbugs/issue9110.go
@@ -0,0 +1,90 @@
+// run
+
+// Copyright 2014 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.
+
+// Scenario that used to leak arbitrarily many SudoG structs.
+// See golang.org/issue/9110.
+
+package main
+
+import (
+	"runtime"
+	"runtime/debug"
+	"sync"
+	"time"
+)
+
+func main() {
+	debug.SetGCPercent(1000000) // only GC when we ask for GC
+
+	var stats, stats1, stats2 runtime.MemStats
+
+	release := func() {}
+	for i := 0; i < 20; i++ {
+		if i == 10 {
+			// Should be warmed up by now.
+			runtime.ReadMemStats(&stats1)
+		}
+
+		c := make(chan int)
+		for i := 0; i < 10; i++ {
+			go func() {
+				select {
+				case <-c:
+				case <-c:
+				case <-c:
+				}
+			}()
+		}
+		time.Sleep(1 * time.Millisecond)
+		release()
+
+		close(c) // let select put its sudog's into the cache
+		time.Sleep(1 * time.Millisecond)
+
+		// pick up top sudog
+		var cond1 sync.Cond
+		var mu1 sync.Mutex
+		cond1.L = &mu1
+		go func() {
+			mu1.Lock()
+			cond1.Wait()
+			mu1.Unlock()
+		}()
+		time.Sleep(1 * time.Millisecond)
+
+		// pick up next sudog
+		var cond2 sync.Cond
+		var mu2 sync.Mutex
+		cond2.L = &mu2
+		go func() {
+			mu2.Lock()
+			cond2.Wait()
+			mu2.Unlock()
+		}()
+		time.Sleep(1 * time.Millisecond)
+
+		// put top sudog back
+		cond1.Broadcast()
+		time.Sleep(1 * time.Millisecond)
+
+		// drop cache on floor
+		runtime.GC()
+
+		// release cond2 after select has gotten to run
+		release = func() {
+			cond2.Broadcast()
+			time.Sleep(1 * time.Millisecond)
+		}
+	}
+
+	runtime.GC()
+
+	runtime.ReadMemStats(&stats2)
+
+	if int(stats2.HeapObjects)-int(stats1.HeapObjects) > 20 { // normally at most 1 or 2; was 300 with leak
+		print("BUG: object leak: ", stats.HeapObjects, " -> ", stats1.HeapObjects, " -> ", stats2.HeapObjects, "\n")
+	}
+}