diff --git a/ta/os_test/os_test.c b/ta/os_test/os_test.c
index d695c78..04128d3 100644
--- a/ta/os_test/os_test.c
+++ b/ta/os_test/os_test.c
@@ -989,7 +989,6 @@
 	long int stack_addr = (long int)&stack;
 	void (*volatile null_fn_ptr)(void) = NULL;
 	char *zero_size_malloc = NULL;
-	volatile char c = 0;
 
 	if (param_types != TEE_PARAM_TYPES(TEE_PARAM_TYPE_VALUE_INPUT, 0, 0, 0) &&
 	    param_types != TEE_PARAM_TYPES(TEE_PARAM_TYPE_VALUE_INPUT,
@@ -1016,7 +1015,8 @@
 		zero_size_malloc = TEE_Malloc(0, 0);
 		if (!zero_size_malloc)
 			return TEE_ERROR_GENERIC;
-		c = *zero_size_malloc;
+		if (*zero_size_malloc)
+			return TEE_ERROR_GENERIC;
 		break;
 	case 7:
 		zero_size_malloc = TEE_Malloc(0, 0);