Lock the subnet mutex only when trying to find peers, so the mutex is not locked when dialing peers.

beacon-chain/p2p/broadcaster.go

@@ -123,9 +123,6 @@ func (s *Service) internalBroadcastAttestation(ctx context.Context, subnet uint6
 	if !hasPeer {
 		attestationBroadcastAttempts.Inc()
 		if err := func() error {
-			s.subnetLocker(subnet).Lock()
-			defer s.subnetLocker(subnet).Unlock()
-
 			if err := s.FindAndDialPeersWithSubnets(ctx, AttestationSubnetTopicFormat, forkDigest, minimumPeersPerSubnetForBroadcast, map[uint64]bool{subnet: true}); err != nil {
 				return errors.Wrap(err, "find peers with subnets")
 			}

beacon-chain/p2p/subnets.go

@@ -110,6 +110,11 @@ func (s *Service) FindAndDialPeersWithSubnets(
 		}
 
 		peersToDial, err := func() ([]*enode.Node, error) {
+			for subnet := range defectiveSubnets {
+				s.subnetLocker(subnet).Lock()
+				defer s.subnetLocker(subnet).Unlock()
+			}
+
 			ctx, cancel := context.WithTimeout(ctx, batchPeriod)
 			defer cancel()
 

changelog/manu-find-peers-subnets.md

@@ -0,0 +1,2 @@
+### Fixed
+- Lock the subnet mutex only when trying to find peers, so the mutex is not locked when dialing peers.