diff --git a/blockstore/splitstore/splitstore_check.go b/blockstore/splitstore/splitstore_check.go
index a36d0b78d..0b4cfe044 100644
--- a/blockstore/splitstore/splitstore_check.go
+++ b/blockstore/splitstore/splitstore_check.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -67,7 +68,10 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 	}
 	defer output.Close() //nolint:errcheck
 
+	var mx sync.Mutex
 	write := func(format string, args ...interface{}) {
+		mx.Lock()
+		defer mx.Unlock()
 		_, err := fmt.Fprintf(output, format+"\n", args...)
 		if err != nil {
 			log.Warnf("error writing check output: %s", err)
@@ -82,7 +86,8 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 	write("compaction index: %d", s.compactionIndex)
 	write("--")
 
-	var coldCnt, missingCnt int64
+	coldCnt := new(int64)
+	missingCnt := new(int64)
 
 	visitor, err := s.markSetEnv.Create("check", 0)
 	if err != nil {
@@ -111,10 +116,10 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 			}
 
 			if has {
-				coldCnt++
+				atomic.AddInt64(coldCnt, 1)
 				write("cold object reference: %s", c)
 			} else {
-				missingCnt++
+				atomic.AddInt64(missingCnt, 1)
 				write("missing object reference: %s", c)
 				return errStopWalk
 			}
@@ -128,9 +133,9 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 		return err
 	}
 
-	log.Infow("check done", "cold", coldCnt, "missing", missingCnt)
+	log.Infow("check done", "cold", *coldCnt, "missing", *missingCnt)
 	write("--")
-	write("cold: %d missing: %d", coldCnt, missingCnt)
+	write("cold: %d missing: %d", *coldCnt, *missingCnt)
 	write("DONE")
 
 	return nil
diff --git a/blockstore/splitstore/splitstore_warmup.go b/blockstore/splitstore/splitstore_warmup.go
index 977c4d392..0670bd0f6 100644
--- a/blockstore/splitstore/splitstore_warmup.go
+++ b/blockstore/splitstore/splitstore_warmup.go
@@ -1,6 +1,7 @@
 package splitstore
 
 import (
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -55,10 +56,11 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 	if WarmupBoundary < epoch {
 		boundaryEpoch = epoch - WarmupBoundary
 	}
+	var mx sync.Mutex
 	batchHot := make([]blocks.Block, 0, batchSize)
-	count := int64(0)
-	xcount := int64(0)
-	missing := int64(0)
+	count := new(int64)
+	xcount := new(int64)
+	missing := new(int64)
 
 	visitor, err := s.markSetEnv.Create("warmup", 0)
 	if err != nil {
@@ -73,7 +75,7 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 				return errStopWalk
 			}
 
-			count++
+			atomic.AddInt64(count, 1)
 
 			has, err := s.hot.Has(s.ctx, c)
 			if err != nil {
@@ -87,22 +89,25 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 			blk, err := s.cold.Get(s.ctx, c)
 			if err != nil {
 				if err == bstore.ErrNotFound {
-					missing++
+					atomic.AddInt64(missing, 1)
 					return errStopWalk
 				}
 				return err
 			}
 
-			xcount++
+			atomic.AddInt64(xcount, 1)
 
+			mx.Lock()
 			batchHot = append(batchHot, blk)
 			if len(batchHot) == batchSize {
 				err = s.hot.PutMany(s.ctx, batchHot)
 				if err != nil {
+					mx.Unlock()
 					return err
 				}
 				batchHot = batchHot[:0]
 			}
+			mx.Unlock()
 
 			return nil
 		})
@@ -118,9 +123,9 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 		}
 	}
 
-	log.Infow("warmup stats", "visited", count, "warm", xcount, "missing", missing)
+	log.Infow("warmup stats", "visited", *count, "warm", *xcount, "missing", *missing)
 
-	s.markSetSize = count + count>>2 // overestimate a bit
+	s.markSetSize = *count + *count>>2 // overestimate a bit
 	err = s.ds.Put(s.ctx, markSetSizeKey, int64ToBytes(s.markSetSize))
 	if err != nil {
 		log.Warnf("error saving mark set size: %s", err)