[PATCH v10 bpf-next 2/2] selftests/bpf: Add selftests for the invocation of bpf_lwt_xmit_push_encap

From: Feng Yang

Date: Wed Mar 04 2026 - 04:46:51 EST


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/prog_tests/lwt_misc.c | 9 ++++++++
tools/testing/selftests/bpf/progs/lwt_misc.c | 22 +++++++++++++++++++
2 files changed, 31 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/lwt_misc.c
create mode 100644 tools/testing/selftests/bpf/progs/lwt_misc.c

diff --git a/tools/testing/selftests/bpf/prog_tests/lwt_misc.c b/tools/testing/selftests/bpf/prog_tests/lwt_misc.c
new file mode 100644
index 000000000000..6940fca38512
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/lwt_misc.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "lwt_misc.skel.h"
+
+void test_lwt_misc(void)
+{
+ RUN_TESTS(lwt_misc);
+}
diff --git a/tools/testing/selftests/bpf/progs/lwt_misc.c b/tools/testing/selftests/bpf/progs/lwt_misc.c
new file mode 100644
index 000000000000..aa638a4f2922
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/lwt_misc.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+SEC("lwt_xmit")
+__success __retval(0)
+int test_missing_dst_call_bpf_lwt_xmit_push_encap(struct __sk_buff *skb)
+{
+ struct iphdr iph;
+
+ __builtin_memset(&iph, 0, sizeof(struct iphdr));
+ iph.ihl = 5;
+ iph.version = 4;
+
+ bpf_lwt_push_encap(skb, BPF_LWT_ENCAP_IP, &iph, sizeof(struct iphdr));
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.43.0