Re: [Qemu-devel] [PATCH for-2.5 v4 1/4] vhost-user-test: fix chardriver race

["Alex Bennée" <alex.bennee@linaro.org>]

marcandre.lureau@redhat.com writes:

> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> vhost-user-tests uses a helper thread to dispatch the vhost-user servers
> sources. However the CharDriverState is not thread-safe. Therefore, when
> it's given to the thread, it shouldn't be manipulated concurrently.
>
> We dispatch cleaning the server in an idle source. By the end of the
> test, we ensure not to leave anything behind by joining the thread and
> finishing the sources dispatch.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  tests/vhost-user-test.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
> index e4c36af..261f4b7 100644
> --- a/tests/vhost-user-test.c
> +++ b/tests/vhost-user-test.c
> @@ -216,8 +216,7 @@ static void read_guest_mem(TestServer *s)
>
>  static void *thread_function(void *data)
>  {
> -    GMainLoop *loop;
> -    loop = g_main_loop_new(NULL, FALSE);
> +    GMainLoop *loop = data;
>      g_main_loop_run(loop);
>      return NULL;
>  }
> @@ -389,7 +388,7 @@ static TestServer *test_server_new(const gchar *name)
>      g_strdup_printf(QEMU_CMD extra, (mem), (mem), (root), (s)->chr_name,       \
>                      (s)->socket_path, (s)->chr_name, ##__VA_ARGS__)
>
> -static void test_server_free(TestServer *server)
> +static gboolean _test_server_free(TestServer *server)
>  {
>      int i;
>
> @@ -406,9 +405,15 @@ static void test_server_free(TestServer *server)
>      unlink(server->socket_path);
>      g_free(server->socket_path);
>
> -
>      g_free(server->chr_name);
>      g_free(server);
> +
> +    return FALSE;
> +}
> +
> +static void test_server_free(TestServer *server)
> +{
> +    g_idle_add((GSourceFunc)_test_server_free, server);
>  }
>
>  static void wait_for_log_fd(TestServer *s)
> @@ -590,6 +595,8 @@ int main(int argc, char **argv)
>      char *qemu_cmd = NULL;
>      int ret;
>      char template[] = "/tmp/vhost-test-XXXXXX";
> +    GMainLoop *loop;
> +    GThread *thread;
>
>      g_test_init(&argc, &argv, NULL);
>
> @@ -612,8 +619,9 @@ int main(int argc, char **argv)
>
>      server = test_server_new("test");
>
> +    loop = g_main_loop_new(NULL, FALSE);
>      /* run the main loop thread so the chardev may operate */
> -    g_thread_new(NULL, thread_function, NULL);
> +    thread = g_thread_new(NULL, thread_function, loop);
>
>      qemu_cmd = GET_QEMU_CMD(server);
>
> @@ -632,6 +640,14 @@ int main(int argc, char **argv)
>      /* cleanup */
>      test_server_free(server);
>
> +    /* finish the helper thread and dispatch pending sources */
> +    g_main_loop_quit(loop);
> +    g_thread_join(thread);
> +    while (g_main_context_pending(NULL)) {
> +        g_main_context_iteration (NULL, TRUE);
> +    }
> +    g_main_loop_unref(loop);
> +
>      ret = rmdir(tmpfs);
>      if (ret != 0) {
>          g_test_message("unable to rmdir: path (%s): %s\n",


--
Alex Bennée