diff --git a/compiler-rt/lib/msan/tests/CMakeLists.txt b/compiler-rt/lib/msan/tests/CMakeLists.txt
index efd370baeae6f..6c0520d984263 100644
--- a/compiler-rt/lib/msan/tests/CMakeLists.txt
+++ b/compiler-rt/lib/msan/tests/CMakeLists.txt
@@ -8,6 +8,7 @@ include_directories(../..)
 set(MSAN_LIBCXX_CFLAGS
   -fsanitize=memory
   -fsanitize-memory-track-origins
+  -fno-sanitize-memory-param-retval  # unittests test mostly this mode.
   -Wno-pedantic
   -Xclang -fdepfile-entry=${COMPILER_RT_OUTPUT_DIR}/share/msan_ignorelist.txt
   )
@@ -41,6 +42,7 @@ set(MSAN_UNITTEST_COMMON_CFLAGS
   -Wno-uninitialized
   -Werror=sign-compare
   -Wno-gnu-zero-variadic-macro-arguments
+  -fno-sanitize-memory-param-retval  # unittests test mostly this mode.
 )
 # Remove -stdlib= which is unused when passing -nostdinc++.
 string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})