wlserver: Fix syncobj crash

Some apps do destruction on other queues which breaks stuff here. Instead handle m_pWlSurfaceInfo being NULL elegantly from both sides.

Author: misyltoad

src/WaylandServer/LinuxDrmSyncobj.h

@@ -45,8 +45,7 @@ namespace gamescope::WaylandServer
 
 		~CLinuxDrmSyncobjSurface()
 		{
-			assert( m_pWlSurfaceInfo->pSyncobjSurface == this );
-			m_pWlSurfaceInfo->pSyncobjSurface = nullptr;
+			Detach();
 		}
 
 		bool HasExplicitSync() const
@@ -70,6 +69,17 @@ namespace gamescope::WaylandServer
 			return std::make_shared<CReleaseTimelinePoint>( m_pReleaseTimeline, m_ulReleasePoint );
 		}
 
+		void Detach()
+		{
+			if ( m_pWlSurfaceInfo )
+			{
+				assert( m_pWlSurfaceInfo->pSyncobjSurface == this );
+				m_pWlSurfaceInfo->pSyncobjSurface = nullptr;
+			}
+
+			m_pWlSurfaceInfo = nullptr;
+		}
+
 	protected:
 
 		void SetAcquirePoint( wl_resource *pWlTimeline, uint32_t uPointHi, uint32_t uPointLo )

src/wlserver.cpp

@@ -599,7 +599,8 @@ static void handle_wl_surface_destroy( struct wl_listener *l, void *data )
 
 	if ( surf->pSyncobjSurface )
 	{
-		wl_resource_destroy( surf->pSyncobjSurface->GetResource() );
+		surf->pSyncobjSurface->Detach();
+		assert( surf->pSyncobjSurface == nullptr );
 	}
 
 	surf->wlr->data = nullptr;