bpf/tests: Add test case flag for verifier zero-extension

This patch adds a new flag to indicate that the verified did insert
zero-extensions, even though the verifier is not being run for any
of the tests.
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-9-johan.almbladh@anyfinetworks.com

lib/test_bpf.c

@@ -52,6 +52,7 @@
 #define FLAG_NO_DATA		BIT(0)
 #define FLAG_EXPECTED_FAIL	BIT(1)
 #define FLAG_SKB_FRAG		BIT(2)
+#define FLAG_VERIFIER_ZEXT	BIT(3)
 
 enum {
 	CLASSIC  = BIT(6),	/* Old BPF instructions only. */
@@ -11280,6 +11281,8 @@ static struct bpf_prog *generate_filter(int which, int *err)
 		fp->type = BPF_PROG_TYPE_SOCKET_FILTER;
 		memcpy(fp->insnsi, fptr, fp->len * sizeof(struct bpf_insn));
 		fp->aux->stack_depth = tests[which].stack_depth;
+		fp->aux->verifier_zext = !!(tests[which].aux &
+					    FLAG_VERIFIER_ZEXT);
 
 		/* We cannot error here as we don't need type compatibility
 		 * checks.