diff --git a/replication/logic/replication_logic.go b/replication/logic/replication_logic.go
index ff0e3d6..13458b7 100644
--- a/replication/logic/replication_logic.go
+++ b/replication/logic/replication_logic.go
@@ -14,6 +14,7 @@ import (
 	"github.com/zrepl/zrepl/replication/logic/pdu"
 	"github.com/zrepl/zrepl/replication/report"
 	"github.com/zrepl/zrepl/util/bytecounter"
+	"github.com/zrepl/zrepl/util/chainlock"
 	"github.com/zrepl/zrepl/util/envconst"
 	"github.com/zrepl/zrepl/util/semaphore"
 	"github.com/zrepl/zrepl/zfs"
@@ -147,8 +148,12 @@ type Step struct {
 	parent   *Filesystem
 	from, to *pdu.FilesystemVersion // compat
 
-	byteCounter  bytecounter.StreamCopier
 	expectedSize int64 // 0 means no size estimate present / possible
+
+	// byteCounter is nil initially, and set later in Step.doReplication
+	// => concurrent read of that pointer from Step.ReportInfo must be protected
+	byteCounter    bytecounter.StreamCopier
+	byteCounterMtx chainlock.L
 }
 
 func (s *Step) TargetEquals(other driver.Step) bool {
@@ -172,10 +177,15 @@ func (s *Step) Step(ctx context.Context) error {
 }
 
 func (s *Step) ReportInfo() *report.StepInfo {
+
+	// get current byteCounter value
 	var byteCounter int64
+	s.byteCounterMtx.Lock()
 	if s.byteCounter != nil {
 		byteCounter = s.byteCounter.Count()
 	}
+	s.byteCounterMtx.Unlock()
+
 	// FIXME stick to zfs convention of from and to
 	from := ""
 	if s.from != nil {
@@ -457,8 +467,12 @@ func (s *Step) doReplication(ctx context.Context) error {
 	defer sstreamCopier.Close()
 
 	// Install a byte counter to track progress + for status report
-	s.byteCounter = bytecounter.NewStreamCopier(sstreamCopier)
+	byteCountingStream := bytecounter.NewStreamCopier(sstreamCopier)
+	s.byteCounterMtx.Lock()
+	s.byteCounter = byteCountingStream
+	s.byteCounterMtx.Unlock()
 	defer func() {
+		defer s.byteCounterMtx.Lock().Unlock()
 		s.parent.promBytesReplicated.Add(float64(s.byteCounter.Count()))
 	}()
 
@@ -467,7 +481,7 @@ func (s *Step) doReplication(ctx context.Context) error {
 		ClearResumeToken: !sres.UsedResumeToken,
 	}
 	log.Debug("initiate receive request")
-	_, err = s.receiver.Receive(ctx, rr, s.byteCounter)
+	_, err = s.receiver.Receive(ctx, rr, byteCountingStream)
 	if err != nil {
 		log.
 			WithError(err).