Fix data rase on mset.cfg

Signed-off-by: Evan Anderson <[email protected]>

Author: evankanderson

server/jetstream.go

@@ -1556,12 +1556,16 @@ func (a *Account) filteredStreams(filter string) []*stream {
 	var msets []*stream
 	for _, mset := range jsa.streams {
 		if filter != _EMPTY_ {
-			for _, subj := range mset.cfg.Subjects {
-				if SubjectsCollide(filter, subj) {
-					msets = append(msets, mset)
-					break
+			func() {
+				mset.cfgMu.RLock()
+				defer mset.cfgMu.RUnlock()
+				for _, subj := range mset.cfg.Subjects {
+					if SubjectsCollide(filter, subj) {
+						msets = append(msets, mset)
+						break
+					}
 				}
-			}
+			}()
 		} else {
 			msets = append(msets, mset)
 		}