Merge pull request #32244 from tksm/fix-cache-race

Automatic merge from submit-queue LRUExpireCache#Get requires write lock **What this PR does / why we need it**: [LRUExpireCache#Get](https://github.com/kubernetes/kubernetes/blob/dbfad789e35979083b8d4b35a4cb405c324cc485/pkg/util/cache/lruexpirecache.go#L48) requires write lock since [groupcache/lru#Get](https://github.com/golang/groupcache/blob/a6b377e3400b08991b80d6805d627f347f983866/lru/lru.go#L74) needs to manipulate its list to track recently used item. Currently it uses read lock so it may introduce race condition. - [test code which introduces race condition with current LRUExpireCache#Get](https://gist.github.com/tksm/17c7a610ed0574c165e6f6edeca351b7#file-lru_race_test-go) **Which issue this PR fixes** #31081

Merge pull request #32244 from tksm/fix-cache-race
804de8a1 · Kubernetes Submit Queue · GitHub · f052de66 · 0bd47567 · 804de8a1
Commit 804de8a1 authored Sep 13, 2016 by Kubernetes Submit Queue Committed by GitHub Sep 13, 2016
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lruexpirecache.go pkg/util/cache/lruexpirecache.go +3 -3

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--- a/pkg/util/cache/lruexpirecache.go
+++ b/pkg/util/cache/lruexpirecache.go
@@ -25,7 +25,7 @@ import (
 type LRUExpireCache struct {
 	cache *lru.Cache
-	lock  sync.RWMutex
+	lock  sync.Mutex
 }
 func NewLRUExpireCache(maxSize int) *LRUExpireCache {
@@ -46,8 +46,8 @@ func (c *LRUExpireCache) Add(key lru.Key, value interface{}, ttl time.Duration) 
 }
 func (c *LRUExpireCache) Get(key lru.Key) (interface{}, bool) {
-	c.lock.RLock()
+	c.lock.Lock()
-	defer c.lock.RUnlock()
+	defer c.lock.Unlock()
 	e, ok := c.cache.Get(key)
 	if !ok {
 		return nil, false