Hold a read lock while canceling a snapshot watch. (#507)

Holding a read lock is sufficient to ensure that the status entry is stable when cancelling watches This updates #503. Signed-off-by: James Peach <[email protected]>
envoyproxy · Oct 25, 2021 · 67cd1a1 · 67cd1a1
1 parent 32c756f
commit 67cd1a1
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/pkg/cache/v3/simple.go b/pkg/cache/v3/simple.go
@@ -364,8 +364,8 @@ func (cache *snapshotCache) nextWatchID() int64 {
 func (cache *snapshotCache) cancelWatch(nodeID string, watchID int64) func() {
 	return func() {
 		// uses the cache mutex
-		cache.mu.Lock()
-		defer cache.mu.Unlock()
+		cache.mu.RLock()
+		defer cache.mu.RUnlock()
 		if info, ok := cache.status[nodeID]; ok {
 			info.mu.Lock()
 			delete(info.watches, watchID)
@@ -506,8 +506,8 @@ func (cache *snapshotCache) nextDeltaWatchID() int64 {
 // cancellation function for cleaning stale delta watches
 func (cache *snapshotCache) cancelDeltaWatch(nodeID string, watchID int64) func() {
 	return func() {
-		cache.mu.Lock()
-		defer cache.mu.Unlock()
+		cache.mu.RLock()
+		defer cache.mu.RUnlock()
 		if info, ok := cache.status[nodeID]; ok {
 			info.mu.Lock()
 			delete(info.deltaWatches, watchID)