[PATCH v8 bpf-next 2/2] selftests/bpf: Add selftests for the invocation of bpf_lwt_xmit_push_encap

[Feng Yang]

From: Feng Yang <yangfeng@xxxxxxxxxx>

Calling bpf_lwt_xmit_push_encap will not cause a crash when dst is missing.

Signed-off-by: Feng Yang <yangfeng@xxxxxxxxxx>
---
 .../selftests/bpf/progs/verifier_lwt.c        | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_lwt.c b/tools/testing/selftests/bpf/progs/verifier_lwt.c
index 5ab746307309..9cef07e6eceb 100644
--- a/tools/testing/selftests/bpf/progs/verifier_lwt.c
+++ b/tools/testing/selftests/bpf/progs/verifier_lwt.c
@@ -231,4 +231,24 @@ __naked void not_permitted_for_lwt_prog(void)
 	: __clobber_all);
 }
 
+SEC("lwt_xmit")
+__description("missing dst when calling bpf_lwt_xmit_push_encap")
+__success __retval(0)
+__naked void missing_dst_call_bpf_lwt_xmit_push_encap(void)
+{
+	asm volatile ("					\
+	r9 = 69;					\
+	r3 = r10;					\
+	r3 += -32;					\
+	*(u64 *)(r3 + 0) = r9;				\
+	r2 = 2;						\
+	r4 = 20;					\
+	call %[bpf_lwt_push_encap];			\
+	r0 = 0;						\
+	exit;						\
+"	:
+	: __imm(bpf_lwt_push_encap)
+	: __clobber_all);
+}
+
 char _license[] SEC("license") = "GPL";
-- 
2.43.0