diff --git a/build b/build
index 2d2ee5cf1..565d0732a 100755
--- a/build
+++ b/build
@@ -16,7 +16,7 @@ GO_LDFLAGS="$GO_LDFLAGS -X ${REPO_PATH}/version.GitSHA=${GIT_SHA}"
 toggle_failpoints() {
 	mode="$1"
 	if command -v gofail >/dev/null 2>&1; then
-		gofail "$mode" etcdserver/ mvcc/backend/
+		gofail "$mode" etcdserver/ mvcc/backend/ wal/
 	elif [[ "$mode" != "disable" ]]; then
 		echo "FAILPOINTS set but gofail not found"
 		exit 1
diff --git a/wal/wal.go b/wal/wal.go
index 2ce3dc411..072ef93fc 100644
--- a/wal/wal.go
+++ b/wal/wal.go
@@ -949,7 +949,10 @@ func (w *WAL) Save(st raftpb.HardState, ents []raftpb.Entry) error {
 	}
 	if curOff < SegmentSizeBytes {
 		if mustSync {
-			return w.sync()
+			// gofail: var walBeforeSync struct{}
+			err = w.sync()
+			// gofail: var walAfterSync struct{}
+			return err
 		}
 		return nil
 	}