diff --git a/tools/run_tests/run_sanity.sh b/tools/run_tests/run_sanity.sh
index 32e25661fa932af14a87627e3e511c01ed4dced0..da85ad5872b4dbfa5a5fbac9e8252b7a6cfa445f 100755
--- a/tools/run_tests/run_sanity.sh
+++ b/tools/run_tests/run_sanity.sh
@@ -52,7 +52,7 @@ diff -u $submodules $want_submodules
 
 rm $submodules $want_submodules
 
-if git ls-files cache.mk --error-unmatch &> /dev/null ; then
+if ! git ls-files cache.mk --error-unmatch &> /dev/null ; then
   echo "Please don't commit cache.mk"
   exit 1
 fi