On 2025-06-09 10:08:53, Jiayuan Chen wrote:
> The selftest can reproduce an issue where using bpf_msg_pop_data() in
> ktls causes errors on the receiving end.
>
> Signed-off-by: Jiayuan Chen <jiayuan.c...@linux.dev>
> ---
Reviewed-by: John Fastabend <john.fastab...@gmail.com>
> .../selftests/bpf/prog_tests/sockmap_ktls.c | 91 +++++++++++++++++++
> .../selftests/bpf/progs/test_sockmap_ktls.c | 4 +
> 2 files changed, 95 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
> b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
> index b6c471da5c28..b87e7f39e15a 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
> @@ -314,6 +314,95 @@ static void test_sockmap_ktls_tx_no_buf(int family, int
> sotype, bool push)
> test_sockmap_ktls__destroy(skel);
> }
>
> +static void test_sockmap_ktls_tx_pop(int family, int sotype)
> +{
> + char msg[37] = "0123456789abcdefghijklmnopqrstuvwxyz\0";
> + int c = 0, p = 0, one = 1, sent, recvd;
> + struct test_sockmap_ktls *skel;
> + int prog_fd, map_fd;
> + char rcv[50] = {0};
> + int err;
> + int i, m, r;
> +
> + skel = test_sockmap_ktls__open_and_load();
> + if (!ASSERT_TRUE(skel, "open ktls skel"))
> + return;
> +
> + err = create_pair(family, sotype, &c, &p);
> + if (!ASSERT_OK(err, "create_pair()"))
> + goto out;
> +
> + prog_fd = bpf_program__fd(skel->progs.prog_sk_policy);
> + map_fd = bpf_map__fd(skel->maps.sock_map);
> +
> + err = bpf_prog_attach(prog_fd, map_fd, BPF_SK_MSG_VERDICT, 0);
> + if (!ASSERT_OK(err, "bpf_prog_attach sk msg"))
> + goto out;
> +
> + err = bpf_map_update_elem(map_fd, &one, &c, BPF_NOEXIST);
> + if (!ASSERT_OK(err, "bpf_map_update_elem(c)"))
> + goto out;
> +
> + err = init_ktls_pairs(c, p);
> + if (!ASSERT_OK(err, "init_ktls_pairs(c, p)"))
> + goto out;
> +
> + struct {
> + int pop_start;
> + int pop_len;
> + } pop_policy[] = {
> + /* trim the start */
> + {0, 2},
> + {0, 10},
> + {1, 2},
> + {1, 10},
> + /* trim the end */
> + {35, 2},
> + /* New entries should be added before this line */
> + {-1, -1},
> + };
> +
> + i = 0;
> + while (pop_policy[i].pop_start >= 0) {
> + skel->bss->pop_start = pop_policy[i].pop_start;
> + skel->bss->pop_end = pop_policy[i].pop_len;
> +
> + sent = send(c, msg, sizeof(msg), 0);
> + if (!ASSERT_EQ(sent, sizeof(msg), "send(msg)"))
> + goto out;
Its possible this could actually not send 38B (sent < 38), but then again
it is only 38B so I guess it should never fail? Anyways we have this
case in a few places already I think and its not tripping CI so lets go
for it.
Thanks,
John
> +
> + recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, 1);
> + if (!ASSERT_EQ(recvd, sizeof(msg) - pop_policy[i].pop_len, "pop
> len mismatch"))
> + goto out;
