diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 43df2ea..fed3de2 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -78,7 +78,7 @@
 
   # Lock the file to avoid interlaced writes
   exec 3>> "$DEPCACHE_FILE"
-  flock -x 3
+  flock 3
   echo "$package:$tip" >&3
   exec 3>&-
 }