vcl: fix packetdrill test error
Type: fix
@@ -1988,7 +1988,7 @@ vppcom_session_read_internal (uint32_t session_handle, void *buf, int n,
u8 is_ct;
if (PREDICT_FALSE (!buf))
- return VPPCOM_EINVAL;
+ return VPPCOM_EFAULT;
s = vcl_session_get_w_handle (wrk, session_handle);
if (PREDICT_FALSE (!s || (s->flags & VCL_SESSION_F_IS_VEP)))
