From a25a6b8c53602d2023dd0ad685000dc006179e94 Mon Sep 17 00:00:00 2001
From: Ondrej Holy <oholy@redhat.com>
Date: Mon, 27 Apr 2026 20:12:42 +0000
Subject: [PATCH] [client,x11] fix deadlock on output expose

Defer screen update from xf_event_Expose to after X11 lock is released,
preventing a deadlock between X11 lock and railWindows lock.

Backport of commit a278ff74117444c635c50ffa5084ecf517171f5a.

Adjusted hunk offsets for 2.11.7.

Made-with: Cursor
---
 client/X11/xf_client.c |  3 ++
 client/X11/xf_event.c  | 77 ++++++++++++++++++++++++++++--------------
 client/X11/xf_event.h  |  2 ++
 client/X11/xfreerdp.h  |  4 +++
 4 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/client/X11/xf_client.c b/client/X11/xf_client.c
index bd3eb0d..f14cb55 100644
--- a/client/X11/xf_client.c
+++ b/client/X11/xf_client.c
@@ -516,6 +516,9 @@ static BOOL xf_process_x_events(freerdp* instance)
 		xf_unlock_x11(xfc);
 		if (!status)
 			break;
+		status = xf_event_update_screen(instance);
+		if (!status)
+			break;
 	}
 
 	return status;
diff --git a/client/X11/xf_event.c b/client/X11/xf_event.c
index e1421ad..524e5e3 100644
--- a/client/X11/xf_event.c
+++ b/client/X11/xf_event.c
@@ -324,45 +324,34 @@ void xf_event_adjust_coordinates(xfContext* xfc, int* x, int* y)
 }
 static BOOL xf_event_Expose(xfContext* xfc, const XExposeEvent* event, BOOL app)
 {
-	int x, y;
-	int w, h;
+	WINPR_ASSERT(xfc);
+	WINPR_ASSERT(event);
+
 	rdpSettings* settings = xfc->context.settings;
+	WINPR_ASSERT(settings);
 
 	if (!app && (settings->SmartSizing || settings->MultiTouchGestures))
 	{
-		x = 0;
-		y = 0;
-		w = settings->DesktopWidth;
-		h = settings->DesktopHeight;
+		xfc->exposedArea.x = 0;
+		xfc->exposedArea.y = 0;
+		xfc->exposedArea.w = settings->DesktopWidth;
+		xfc->exposedArea.h = settings->DesktopHeight;
 	}
 	else
 	{
-		x = event->x;
-		y = event->y;
-		w = event->width;
-		h = event->height;
+		xfc->exposedArea.x = event->x;
+		xfc->exposedArea.y = event->y;
+		xfc->exposedArea.w = event->width;
+		xfc->exposedArea.h = event->height;
 	}
 
-	if (!app)
-	{
-		if (xfc->context.gdi->gfx)
-		{
-			xf_OutputExpose(xfc, x, y, w, h);
-			return TRUE;
-		}
-		xf_draw_screen(xfc, x, y, w, h);
-	}
-	else
-	{
-		xfAppWindow* appWindow = xf_AppWindowFromX11Window(xfc, event->window);
-		if (appWindow)
-			xf_UpdateWindowArea(xfc, appWindow, x, y, w, h);
-		xf_rail_return_window(appWindow, FALSE);
-	}
+	xfc->exposedWindow = event->window;
+	xfc->exposeRequested = TRUE;
 
 	return TRUE;
 }
 
+
 static BOOL xf_event_VisibilityNotify(xfContext* xfc, const XVisibilityEvent* event, BOOL app)
 {
 	WINPR_UNUSED(app);
@@ -1180,3 +1169,39 @@ BOOL xf_event_process(freerdp* instance, const XEvent* event)
 	XSync(xfc->display, FALSE);
 	return status;
 }
+
+BOOL xf_event_update_screen(freerdp* instance)
+{
+	WINPR_ASSERT(instance);
+
+	xfContext* xfc = (xfContext*)instance->context;
+	WINPR_ASSERT(xfc);
+
+	rdpSettings* settings = xfc->context.settings;
+	WINPR_ASSERT(settings);
+
+	if (!xfc->exposeRequested)
+		return TRUE;
+	xfc->exposeRequested = FALSE;
+
+	if (!xfc->remote_app)
+	{
+		if (xfc->context.gdi->gfx)
+		{
+			xf_OutputExpose(xfc, xfc->exposedArea.x, xfc->exposedArea.y,
+			                xfc->exposedArea.w, xfc->exposedArea.h);
+			return TRUE;
+		}
+		xf_draw_screen(xfc, xfc->exposedArea.x, xfc->exposedArea.y, xfc->exposedArea.w,
+		               xfc->exposedArea.h);
+	}
+	else
+	{
+		xfAppWindow* appWindow = xf_AppWindowFromX11Window(xfc, xfc->exposedWindow);
+		if (appWindow)
+			xf_UpdateWindowArea(xfc, appWindow, xfc->exposedArea.x, xfc->exposedArea.y,
+			                    xfc->exposedArea.w, xfc->exposedArea.h);
+		xf_rail_return_window(appWindow, FALSE);
+	}
+	return TRUE;
+}
diff --git a/client/X11/xf_event.h b/client/X11/xf_event.h
index 2269d3e..e025d19 100644
--- a/client/X11/xf_event.h
+++ b/client/X11/xf_event.h
@@ -29,6 +29,8 @@ BOOL xf_event_action_script_init(xfContext* xfc);
 void xf_event_action_script_free(xfContext* xfc);
 
 BOOL xf_event_process(freerdp* instance, const XEvent* event);
+
+BOOL xf_event_update_screen(freerdp* instance);
 void xf_event_SendClientEvent(xfContext* xfc, xfWindow* window, Atom atom, unsigned int numArgs,
                               ...);
 
diff --git a/client/X11/xfreerdp.h b/client/X11/xfreerdp.h
index 636e60a..a1a33b2 100644
--- a/client/X11/xfreerdp.h
+++ b/client/X11/xfreerdp.h
@@ -261,6 +261,10 @@ struct xf_context
 	wHashTable* railWindows;
 	xfRailIconCache* railIconCache;
 
+	BOOL exposeRequested;
+	GDI_RGN exposedArea;
+	Window exposedWindow;
+
 	BOOL xkbAvailable;
 	BOOL xrenderAvailable;
 
-- 
2.53.0