vsock/test: Extend transport change null-ptr-deref test

syzkaller reported a lockdep lock order inversion warning[1] due to
commit 687aa0c5581b ("vsock: Fix transport_* TOCTOU"). This was fixed in
commit f7c877e75352 ("vsock: fix lock inversion in
vsock_assign_transport()").

Redo syzkaller's repro by piggybacking on a somewhat related test
implemented in commit 3a764d93385c ("vsock/test: Add test for null ptr
deref when transport changes").

[1]: https://lore.kernel.org/netdev/68f6cdb0.a70a0220.205af.0039.GAE@google.com/

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20251123-vsock_test-linger-lockdep-warn-v1-1-4b1edf9d8cdc@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index d4517386e551e3e3908aabc14bc4608695e9c45f..9e1250790f33d6d6c6ab47d01f6aea9f68961d85 100644 (file)
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -2015,6 +2015,11 @@ static void test_stream_transport_change_client(const struct test_opts *opts)
                        exit(EXIT_FAILURE);
                }
 
+               /* Although setting SO_LINGER does not affect the original test
+                * for null-ptr-deref, it may trigger a lockdep warning.
+                */
+               enable_so_linger(s, 1);
+
                ret = connect(s, (struct sockaddr *)&sa, sizeof(sa));
                /* The connect can fail due to signals coming from the thread,
                 * or because the receiver connection queue is full.
@@ -2352,7 +2357,7 @@ static struct test_case test_cases[] = {
                .run_server = test_stream_nolinger_server,
        },
        {
-               .name = "SOCK_STREAM transport change null-ptr-deref",
+               .name = "SOCK_STREAM transport change null-ptr-deref, lockdep warn",
                .run_client = test_stream_transport_change_client,
                .run_server = test_stream_transport_change_server,
        },