diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index 10360d4ea273..079fb12d59cc 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -19,7 +19,7 @@ static __init bool test_string_check_buf(const char *name, unsigned int flags,
 	if (q_real == q_test && !memcmp(out_test, out_real, q_test))
 		return true;
 
-	pr_warn("Test '%s' failed: flags = %u\n", name, flags);
+	pr_warn("Test '%s' failed: flags = %#x\n", name, flags);
 
 	print_hex_dump(KERN_WARNING, "Input: ", DUMP_PREFIX_NONE, 16, 1,
 		       in, p, true);
@@ -290,7 +290,7 @@ test_string_escape_overflow(const char *in, int p, unsigned int flags, const cha
 
 	q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
 	if (q_real != q_test)
-		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
+		pr_warn("Test '%s' failed: flags = %#x, osz = 0, expected %d, got %d\n",
 			name, flags, q_test, q_real);
 }