Merge lp:~alan-griffiths/mir/fix-1728931 into lp:mir

[Alan Griffiths]

Prevent the (stub-graphics) module being unloaded while a test is using it. (LP: #1728931)

Prevent the (stub-graphics) module being unloaded while a test is using it.

I'm suspicious that same issue (of potentially using/deleting buffers allocated by a graphics platform after the platform unloads) exists more generally, but this fixes the only known case.

[Michał Sawicz (saviq)]

Please resubmit on GitHub: https://github.com/MirServer/mir/tree/fix-1728931

review: Needs Resubmitting

Unmerged revisions

4306. By Alan Griffiths on 2017-10-31

Prevent the graphics platform unloading before the test finishes

=== modified file 'tests/mir_test_framework/async_server_runner.cpp'
--- tests/mir_test_framework/async_server_runner.cpp	2017-09-18 10:57:00 +0000
+++ tests/mir_test_framework/async_server_runner.cpp	2017-10-31 18:01:05 +0000
@@ -78,6 +78,12 @@
     env.emplace_back(key, value);
 }
 
+namespace
+{
+// This avoids an intermittent shutdown crash deleting a stub-graphics buffer (LP: #1728931)
+std::shared_ptr<void> delay_unloading_graphics_platform;
+}
+
 void mtf::AsyncServerRunner::start_server()
 {
     set_window_management_policy(server);
@@ -100,6 +106,8 @@
 
     server.apply_settings();
 
+    delay_unloading_graphics_platform = server.the_graphics_platform();
+
     mt::AutoJoinThread t([&]
         {
             try
@@ -143,7 +151,10 @@
     server_thread.stop();
 }
 
-mtf::AsyncServerRunner::~AsyncServerRunner() noexcept = default;
+mtf::AsyncServerRunner::~AsyncServerRunner() noexcept
+{
+    delay_unloading_graphics_platform.reset();
+}
 
 auto mtf::AsyncServerRunner::new_connection() -> std::string
 {