[PATCH 6.8 030/158] selftests/tcp_ao: Make RST tests less flaky

Greg Kroah-Hartman
2024-04-23T21:41:23Z

From: Dmitry Safonov <0x7f454c46@gmail.com>

[ Upstream commit 4225dfa4535f219b03ae14147d9c6e7e82ec8df4 ]

Currently, "active reset" cases are flaky, because select() is called
for 3 sockets, while only 2 are expected to receive RST.
The idea of the third socket was to get into request_sock_queue,
but the test mistakenly attempted to connect() after the listener
socket was shut down.

Repair this test, it's important to check the different kernel
code-paths for signing RST TCP-AO segments.

Fixes: c6df7b2361d7 ("selftests/net: Add TCP-AO RST test")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/net/tcp_ao/rst.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/net/tcp_ao/rst.c b/tools/testing/selftests/net/tcp_ao/rst.c
index 7df8b8700e39e..a2fe88d35ac06 100644
--- a/tools/testing/selftests/net/tcp_ao/rst.c
+++ b/tools/testing/selftests/net/tcp_ao/rst.c
@@ -256,8 +256,6 @@ static int test_wait_fds(int sk[], size_t nr, bool is_writable[],

static void test_client_active_rst(unsigned int port)
{
- /* one in queue, another accept()ed */
- unsigned int wait_for = backlog + 2;
int i, sk[3], err;
bool is_writable[ARRAY_SIZE(sk)] = {false};
unsigned int last = ARRAY_SIZE(sk) - 1;
@@ -275,16 +273,20 @@ static void test_client_active_rst(unsigned int port)
for (i = 0; i < last; i++) {
err = _test_connect_socket(sk[i], this_ip_dest, port,
(i == 0) ? TEST_TIMEOUT_SEC : -1);
-
if (err < 0)
test_error("failed to connect()");
}

- synchronize_threads(); /* 2: connection accept()ed, another queued */
- err = test_wait_fds(sk, last, is_writable, wait_for, TEST_TIMEOUT_SEC);
+ synchronize_threads(); /* 2: two connections: one accept()ed, another queued */
+ err = test_wait_fds(sk, last, is_writable, last, TEST_TIMEOUT_SEC);
if (err < 0)
test_error("test_wait_fds(): %d", err);

+ /* async connect() with third sk to get into request_sock_queue */
+ err = _test_connect_socket(sk[last], this_ip_dest, port, -1);
+ if (err < 0)
+ test_error("failed to connect()");
+
synchronize_threads(); /* 3: close listen socket */
if (test_client_verify(sk[0], packet_sz, quota / packet_sz, TEST_TIMEOUT_SEC))
test_fail("Failed to send data on connected socket");
@@ -292,13 +294,14 @@ static void test_client_active_rst(unsigned int port)
test_ok("Verified established tcp connection");

synchronize_threads(); /* 4: finishing up */
- err = _test_connect_socket(sk[last], this_ip_dest, port, -1);
- if (err < 0)
- test_error("failed to connect()");

synchronize_threads(); /* 5: closed active sk */
- err = test_wait_fds(sk, ARRAY_SIZE(sk), NULL,
- wait_for, TEST_TIMEOUT_SEC);
+ /*
+ * Wait for 2 connections: one accepted, another in the accept queue,
+ * the one in request_sock_queue won't get fully established, so
+ * doesn't receive an active RST, see inet_csk_listen_stop().
+ */
+ err = test_wait_fds(sk, last, NULL, last, TEST_TIMEOUT_SEC);
if (err < 0)
test_error("select(): %d", err);

--
2.43.0