swarm/pss: mutex lifecycle fixed (#19045)

(cherry picked from commit b30109df)

swarm/pss/protocol.go

@@ -228,6 +228,7 @@ func ToP2pMsg(msg []byte) (p2p.Msg, error) {
 // to link the peer to.
 // The key must exist in the pss store prior to adding the peer.
 func (p *Protocol) AddPeer(peer *p2p.Peer, topic Topic, asymmetric bool, key string) (p2p.MsgReadWriter, error) {
+	var ok bool
 	rw := &PssReadWriter{
 		Pss:   p.Pss,
 		rw:    make(chan p2p.Msg),
@@ -242,19 +243,21 @@ func (p *Protocol) AddPeer(peer *p2p.Peer, topic Topic, asymmetric bool, key str
 	}
 	if asymmetric {
 		p.Pss.pubKeyPoolMu.Lock()
-		if _, ok := p.Pss.pubKeyPool[key]; !ok {
+		_, ok = p.Pss.pubKeyPool[key]
+		p.Pss.pubKeyPoolMu.Unlock()
+		if !ok {
 			return nil, fmt.Errorf("asym key does not exist: %s", key)
 		}
-		p.Pss.pubKeyPoolMu.Unlock()
 		p.RWPoolMu.Lock()
 		p.pubKeyRWPool[key] = rw
 		p.RWPoolMu.Unlock()
 	} else {
 		p.Pss.symKeyPoolMu.Lock()
-		if _, ok := p.Pss.symKeyPool[key]; !ok {
+		_, ok = p.Pss.symKeyPool[key]
+		p.Pss.symKeyPoolMu.Unlock()
+		if !ok {
 			return nil, fmt.Errorf("symkey does not exist: %s", key)
 		}
-		p.Pss.symKeyPoolMu.Unlock()
 		p.RWPoolMu.Lock()
 		p.symKeyRWPool[key] = rw
 		p.RWPoolMu.Unlock()