P2p active val count lock (#15955)

* Add a lock for p2p computation of active validator count and limit only to topics that need it.

* Changelog fragment

* Update gossip_scoring_params.go

Wrap errors

beacon-chain/p2p/gossip_scoring_params.go

@@ -2,6 +2,7 @@ package p2p
 
 import (
 	"context"
+	"fmt"
 	"math"
 	"net"
 	"reflect"
@@ -106,18 +107,26 @@ func peerScoringParams(colocationWhitelist []*net.IPNet) (*pubsub.PeerScoreParam
 }
 
 func (s *Service) topicScoreParams(topic string) (*pubsub.TopicScoreParams, error) {
-	activeValidators, err := s.retrieveActiveValidators()
-	if err != nil {
-		return nil, err
-	}
 	switch {
 	case strings.Contains(topic, GossipBlockMessage):
 		return defaultBlockTopicParams(), nil
 	case strings.Contains(topic, GossipAggregateAndProofMessage):
+		activeValidators, err := s.retrieveActiveValidators()
+		if err != nil {
+			return nil, fmt.Errorf("failed to compute active validator count for topic %s: %w", GossipAggregateAndProofMessage, err)
+		}
 		return defaultAggregateTopicParams(activeValidators), nil
 	case strings.Contains(topic, GossipAttestationMessage):
+		activeValidators, err := s.retrieveActiveValidators()
+		if err != nil {
+			return nil, fmt.Errorf("failed to compute active validator count for topic %s: %w", GossipAttestationMessage, err)
+		}
 		return defaultAggregateSubnetTopicParams(activeValidators), nil
 	case strings.Contains(topic, GossipSyncCommitteeMessage):
+		activeValidators, err := s.retrieveActiveValidators()
+		if err != nil {
+			return nil, fmt.Errorf("failed to compute active validator count for topic %s: %w", GossipSyncCommitteeMessage, err)
+		}
 		return defaultSyncSubnetTopicParams(activeValidators), nil
 	case strings.Contains(topic, GossipContributionAndProofMessage):
 		return defaultSyncContributionTopicParams(), nil
@@ -142,6 +151,8 @@ func (s *Service) topicScoreParams(topic string) (*pubsub.TopicScoreParams, erro
 }
 
 func (s *Service) retrieveActiveValidators() (uint64, error) {
+	s.activeValidatorCountLock.Lock()
+	defer s.activeValidatorCountLock.Unlock()
 	if s.activeValidatorCount != 0 {
 		return s.activeValidatorCount, nil
 	}

beacon-chain/p2p/service.go

@@ -89,6 +89,7 @@ type Service struct {
 	genesisTime              time.Time
 	genesisValidatorsRoot    []byte
 	activeValidatorCount     uint64
+	activeValidatorCountLock sync.Mutex
 	peerDisconnectionTime    *cache.Cache
 	custodyInfo              *custodyInfo
 	custodyInfoLock          sync.RWMutex // Lock access to custodyInfo

changelog/pvl-active-val-count-lock.md

@@ -0,0 +1,4 @@
+### Fixed
+
+- Changed the behavior of topic subscriptions such that only topics that require the active validator count will compute that value. 
+- Added a Mutex to the computation of active validator count during topic subscription to avoid a race condition where multiple goroutines are computing the same work.