fix the race condition between goroutine and channel on the same leas…

…es to be revoked

server/etcdserver/server.go

@@ -842,33 +842,36 @@ func (s *EtcdServer) run() {
 			f := func(context.Context) { s.applyAll(&ep, &ap) }
 			sched.Schedule(f)
 		case leases := <-expiredLeaseC:
-			s.GoAttach(func() {
-				// Increases throughput of expired leases deletion process through parallelization
-				c := make(chan struct{}, maxPendingRevokes)
-				for _, lease := range leases {
-					select {
-					case c <- struct{}{}:
-					case <-s.stopping:
-						return
-					}
-					lid := lease.ID
-					s.GoAttach(func() {
-						ctx := s.authStore.WithRoot(s.ctx)
-						_, lerr := s.LeaseRevoke(ctx, &pb.LeaseRevokeRequest{ID: int64(lid)})
-						if lerr == nil {
-							leaseExpired.Inc()
-						} else {
-							lg.Warn(
-								"failed to revoke lease",
-								zap.String("lease-id", fmt.Sprintf("%016x", lid)),
-								zap.Error(lerr),
-							)
+			f := func(leases []*lease.Lease) {
+				s.GoAttach(func() {
+					// Increases throughput of expired leases deletion process through parallelization
+					c := make(chan struct{}, maxPendingRevokes)
+					for _, lease := range leases {
+						select {
+						case c <- struct{}{}:
+						case <-s.stopping:
+							return
 						}
-
-						<-c
-					})
-				}
-			})
+						lid := lease.ID
+						s.GoAttach(func() {
+							ctx := s.authStore.WithRoot(s.ctx)
+							_, lerr := s.LeaseRevoke(ctx, &pb.LeaseRevokeRequest{ID: int64(lid)})
+							if lerr == nil {
+								leaseExpired.Inc()
+							} else {
+								lg.Warn(
+									"failed to revoke lease",
+									zap.String("lease-id", fmt.Sprintf("%016x", lid)),
+									zap.Error(lerr),
+								)
+							}
+
+							<-c
+						})
+					}
+				})
+			}
+			f(leases)
 		case err := <-s.errorc:
 			lg.Warn("server error", zap.Error(err))
 			lg.Warn("data-dir used by this member must be removed")