display: Freeze stack when closing X11 display

If two X11 windows were the last two, we'd remove them from the stack
while unmanaging them. That'd hit an assert in
meta_stack_tracker_restack_managed(), resulting in the following crash
when Xwayland exited unexpectedly with two or more X11 windows being the
only windows on the stack:

  #1  g_assertion_message() at ../glib/gtestutils.c:3256
  #2  g_assertion_message_expr() at ../glib/gtestutils.c:3282
  #3  meta_stack_tracker_restack_managed() at ../src/core/stack-tracker.c:1210
  #4  on_stack_changed() at ../src/core/stack.c:142
  #5  _g_closure_invoke_va() at ../gobject/gclosure.c:895
  #6  g_signal_emit_valist() at ../gobject/gsignal.c:3456
  #7  g_signal_emit() at ../gobject/gsignal.c:3606
  #8 meta_stack_changed() at ../src/core/stack.c:265
  #9 meta_stack_remove() at ../src/core/stack.c:324
 #10 meta_window_unmanage() at ../src/core/window.c:1542
 #11 meta_x11_display_unmanage_windows() at ../src/x11/meta-x11-display.c:111
 #12 meta_x11_display_dispose() at ../src/x11/meta-x11-display.c:141
 #13 g_object_run_dispose() at ../gobject/gobject.c:1448
 #14 meta_display_shutdown_x11() at ../src/core/display.c:831

The added test specifically checks that this scenario is handled
gracefully.

Related: https://bugzilla.redhat.com/show_bug.cgi?id=2143637
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2704>
This commit is contained in:
Jonas Ådahl 2022-11-20 20:17:58 +01:00 committed by Marge Bot
parent dec3c49e5a
commit 425e80adc2
2 changed files with 62 additions and 0 deletions

View File

@ -826,9 +826,11 @@ meta_display_shutdown_x11 (MetaDisplay *display)
if (!display->x11_display)
return;
meta_stack_freeze (display->stack);
g_signal_emit (display, display_signals[X11_DISPLAY_CLOSING], 0);
g_object_run_dispose (G_OBJECT (display->x11_display));
g_clear_object (&display->x11_display);
meta_stack_thaw (display->stack);
}
MetaDisplay *

View File

@ -156,11 +156,71 @@ meta_test_xwayland_restart_selection (void)
meta_test_client_destroy (test_client);
}
static void
meta_test_xwayland_crash_only_x11 (void)
{
MetaWaylandCompositor *wayland_compositor =
meta_context_get_wayland_compositor (test_context);
MetaXWaylandManager *xwayland_manager =
meta_wayland_compositor_get_xwayland_manager (wayland_compositor);
MetaDisplay *display = meta_context_get_display (test_context);
MetaTestClient *test_client1;
MetaTestClient *test_client2;
g_autoptr (GError) error = NULL;
g_assert_null (meta_display_list_all_windows (display));
test_client1 = meta_test_client_new (test_context,
"client1", META_WINDOW_CLIENT_TYPE_X11,
&error);
if (!test_client1)
g_error ("Failed to launch test client: %s", error->message);
test_client2 = meta_test_client_new (test_context,
"client1", META_WINDOW_CLIENT_TYPE_X11,
&error);
if (!test_client2)
g_error ("Failed to launch test client: %s", error->message);
ensure_xwayland (test_context);
test_client_do_check (test_client2, "create", "test-window", NULL);
test_client_do_check (test_client1, "create", "test-window", NULL);
test_client_do_check (test_client2, "show", "test-window", NULL);
test_client_do_check (test_client1, "show", "test-window", NULL);
test_client_wait_check (test_client2);
test_client_wait_check (test_client1);
while (!meta_find_window_from_title (test_context, "test/client1/test-window") ||
!meta_find_window_from_title (test_context, "test/client1/test-window"))
g_main_context_iteration (NULL, TRUE);
g_test_expect_message ("libmutter", G_LOG_LEVEL_WARNING,
"*Connection to xwayland lost*");
g_test_expect_message ("libmutter", G_LOG_LEVEL_WARNING,
"X Wayland crashed*; attempting to recover");
if (!meta_xwayland_signal (xwayland_manager, SIGKILL, &error))
g_error ("Failed to signal SIGSEGV to Xwayland");
while (meta_display_get_x11_display (display))
g_main_context_iteration (NULL, TRUE);
g_test_assert_expected_messages ();
g_assert_null (meta_display_list_all_windows (display));
meta_test_client_destroy (test_client1);
meta_test_client_destroy (test_client2);
}
static void
init_tests (void)
{
g_test_add_func ("/backends/xwayland/restart/selection",
meta_test_xwayland_restart_selection);
g_test_add_func ("/backends/xwayland/crash/only-x11",
meta_test_xwayland_crash_only_x11);
}
int