From 2f171d0ed4456c7fa3dcc24b38ae80131bd0d59e Mon Sep 17 00:00:00 2001 From: Philip Withnall Date: Tue, 5 May 2020 11:22:26 +0100 Subject: [PATCH] tests: Fix remaining race in gdbus-connection filter test MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 721e385 left one remaining race in the filter test, with a comment associated with it. Unfortunately, the (seemingly unrelated) changes in #1841 to `GCancellable` seem to have made this remaining race a lot more likely to fail on FreeBSD than before. What’s likely to have happened (although I was unable to reproduce the failure, due to not having a FreeBSD system; I was only able to reproduce the problem as a 3/1000 failure on Linux, which is still worth fixing) is that the atomic write of the `FilterData.serial` to be expected by the filter function sometimes happened after the filter function had executed, so the expected message was dropped and didn’t result in an update to the `FilterData` state. Rework the test so that instead of setting some expectations (on `FilterData`) in one thread and then checking them in another thread, the worker thread just unconditionally returns messages from the filter function to the main thread, and then the main thread checks whether the expected one has been filtered. With this change applied, the `gdbus-connection` test passes 5000 times in a row for me, on Linux; and doesn’t seem to fail any more on the FreeBSD CI machines over a few runs. (Previously it failed on 4/5 runs.) Signed-off-by: Philip Withnall Fixes: #2092 Fixes: #1957 --- gio/tests/gdbus-connection.c | 62 ++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 31 deletions(-) diff --git a/gio/tests/gdbus-connection.c b/gio/tests/gdbus-connection.c index 4fec8d0fd..7bd7a02f4 100644 --- a/gio/tests/gdbus-connection.c +++ b/gio/tests/gdbus-connection.c @@ -817,9 +817,8 @@ test_connection_signal_match_rules (void) * so all accesses must be atomic. */ typedef struct { - guint num_handled; /* (atomic) */ + GAsyncQueue *incoming_queue; /* (element-type GDBusMessage) */ guint num_outgoing; /* (atomic) */ - guint32 serial; /* (atomic) */ } FilterData; /* Runs in a worker thread. */ @@ -830,22 +829,31 @@ filter_func (GDBusConnection *connection, gpointer user_data) { FilterData *data = user_data; - guint32 reply_serial; if (incoming) - { - reply_serial = g_dbus_message_get_reply_serial (message); - if (reply_serial == g_atomic_int_get (&data->serial)) - g_atomic_int_inc (&data->num_handled); - } + g_async_queue_push (data->incoming_queue, g_object_ref (message)); else - { - g_atomic_int_inc (&data->num_outgoing); - } + g_atomic_int_inc (&data->num_outgoing); return message; } +static void +wait_for_filtered_reply (GAsyncQueue *incoming_queue, + guint32 expected_serial) +{ + GDBusMessage *popped_message = NULL; + + while ((popped_message = g_async_queue_pop (incoming_queue)) != NULL) + { + guint32 reply_serial = g_dbus_message_get_reply_serial (popped_message); + g_object_unref (popped_message); + if (reply_serial == expected_serial) + return; + } + + g_assert_not_reached (); +} typedef struct { @@ -933,7 +941,7 @@ static void test_connection_filter (void) { GDBusConnection *c; - FilterData data = { 0, 0, 0 }; + FilterData data = { NULL, 0 }; GDBusMessage *m; GDBusMessage *m2; GDBusMessage *r; @@ -953,6 +961,8 @@ test_connection_filter (void) g_assert_no_error (error); g_assert_nonnull (c); + data.incoming_queue = g_async_queue_new_full (g_object_unref); + data.num_outgoing = 0; filter_id = g_dbus_connection_add_filter (c, filter_func, &data, @@ -965,21 +975,17 @@ test_connection_filter (void) g_dbus_message_set_body (m, g_variant_new ("(s)", "org.freedesktop.DBus")); error = NULL; g_dbus_connection_send_message (c, m, G_DBUS_SEND_MESSAGE_FLAGS_NONE, &serial_temp, &error); - g_atomic_int_set (&data.serial, serial_temp); g_assert_no_error (error); - while (g_atomic_int_get (&data.num_handled) == 0) - g_thread_yield (); + wait_for_filtered_reply (data.incoming_queue, serial_temp); m2 = g_dbus_message_copy (m, &error); g_assert_no_error (error); g_dbus_connection_send_message (c, m2, G_DBUS_SEND_MESSAGE_FLAGS_NONE, &serial_temp, &error); - g_atomic_int_set (&data.serial, serial_temp); g_object_unref (m2); g_assert_no_error (error); - while (g_atomic_int_get (&data.num_handled) == 1) - g_thread_yield (); + wait_for_filtered_reply (data.incoming_queue, serial_temp); m2 = g_dbus_message_copy (m, &error); g_assert_no_error (error); @@ -987,12 +993,10 @@ test_connection_filter (void) /* lock the message to test PRESERVE_SERIAL flag. */ g_dbus_message_lock (m2); g_dbus_connection_send_message (c, m2, G_DBUS_SEND_MESSAGE_FLAGS_PRESERVE_SERIAL, &serial_temp, &error); - g_atomic_int_set (&data.serial, serial_temp); g_object_unref (m2); g_assert_no_error (error); - while (g_atomic_int_get (&data.num_handled) == 2) - g_thread_yield (); + wait_for_filtered_reply (data.incoming_queue, serial_temp); m2 = g_dbus_message_copy (m, &error); g_assert_no_error (error); @@ -1000,17 +1004,16 @@ test_connection_filter (void) m2, G_DBUS_SEND_MESSAGE_FLAGS_NONE, -1, - /* can't do this write atomically - * as filter_func() needs it before - * send_message_with_reply_sync() returns */ - &data.serial, + &serial_temp, NULL, /* GCancellable */ &error); g_object_unref (m2); g_assert_no_error (error); g_assert_nonnull (r); g_object_unref (r); - g_assert_cmpint (g_atomic_int_get (&data.num_handled), ==, 4); + + wait_for_filtered_reply (data.incoming_queue, serial_temp); + g_assert_cmpint (g_async_queue_length (data.incoming_queue), ==, 0); g_dbus_connection_remove_filter (c, filter_id); @@ -1023,12 +1026,11 @@ test_connection_filter (void) &serial_temp, NULL, /* GCancellable */ &error); - g_atomic_int_set (&data.serial, serial_temp); g_object_unref (m2); g_assert_no_error (error); g_assert_nonnull (r); g_object_unref (r); - g_assert_cmpint (g_atomic_int_get (&data.num_handled), ==, 4); + g_assert_cmpint (g_async_queue_length (data.incoming_queue), ==, 0); g_assert_cmpint (g_atomic_int_get (&data.num_outgoing), ==, 4); /* wait for service to be available */ @@ -1101,6 +1103,7 @@ test_connection_filter (void) g_object_unref (c); g_object_unref (m); + g_async_queue_unref (data.incoming_queue); session_bus_down (); } @@ -1268,9 +1271,6 @@ main (int argc, { int ret; - /* FIXME: Add debug for https://gitlab.gnome.org/GNOME/glib/issues/1957 */ - g_setenv ("G_DBUS_DEBUG", "all", TRUE); - g_test_init (&argc, &argv, NULL); /* all the tests rely on a shared main loop */