bpf: Fix tcp_rwnd_kern.c sample program

The program was returning -1 in some cases which is not allowed
by the verifier any longer.

Fixes: 390ee7e29fc8 ("bpf: enforce return code for cgroup-bpf programs")
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/samples/bpf/tcp_rwnd_kern.c b/samples/bpf/tcp_rwnd_kern.c
index 3f2a228f81ce..09ff65b40b31 100644
--- a/samples/bpf/tcp_rwnd_kern.c
+++ b/samples/bpf/tcp_rwnd_kern.c
@@ -38,8 +38,10 @@ int bpf_rwnd(struct bpf_sock_ops *skops)
          * if neither port numberis 55601
          */
         if (bpf_ntohl(skops->remote_port) !=
-            55601 && skops->local_port != 55601)
-                return -1;
+            55601 && skops->local_port != 55601) {
+                skops->reply = -1;
+                return 1;
+        }
 
         op = (int) skops->op;