On Mon, Sep 14, 2020 at 12:43:04PM -0700, Martin KaFai Lau wrote: > For other ARG_PTR_TO_SOCK_COMMON helpers, they are not available to > the tracing prog type. Hence, they are fine to accept PTR_TO_BTF_ID > as ARG_PTR_TO_SOCK_COMMON since the only way for non tracing prog to > get a PTR_TO_BTF_ID is from casting helpers bpf_skc_to_* and > the NULL check on return value must be done first. After looking more, it may not work well. For example, reading request_sock->sk. Need to think a bit. May try out another idea tomorrow or consider adding the OR_NULL arg as you mentioned.