diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index 996dc6645570..534aa405cac7 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -512,14 +512,14 @@ static int test_child_ksm(void)
 
 	/* Test if KSM is enabled for the process. */
 	if (prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) != 1)
-		return -1;
+		return 1;
 
 	/* Test if merge could really happen. */
 	map = __mmap_and_merge_range(0xcf, size, PROT_READ | PROT_WRITE, KSM_MERGE_NONE);
 	if (map == MAP_MERGE_FAIL)
-		return -2;
+		return 2;
 	else if (map == MAP_MERGE_SKIP)
-		return -3;
+		return 3;
 
 	ksm_unmerge();
 	munmap(map, size);
@@ -528,12 +528,14 @@ static int test_child_ksm(void)
 
 static void test_child_ksm_err(int status)
 {
-	if (status == -1)
+	if (status == 1)
 		ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n");
-	else if (status == -2)
+	else if (status == 2)
 		ksft_test_result_fail("Merge in child failed\n");
-	else if (status == -3)
+	else if (status == 3)
 		ksft_test_result_skip("Merge in child skipped\n");
+	else if (status == 4)
+		ksft_test_result_fail("Binary not found\n");
 }
 
 /* Verify that prctl ksm flag is inherited. */
@@ -606,7 +608,7 @@ static void test_prctl_fork_exec(void)
 		char *argv_for_program[] = { prg_name, FORK_EXEC_CHILD_PRG_NAME, NULL };
 
 		execv(prg_name, argv_for_program);
-		return;
+		exit(4);
 	}
 
 	if (waitpid(child_pid, &status, 0) > 0) {