Ensure the Render extension is initialized before calling XESetCloseDisplay

This avoids a potential crash from the Render extension being cleaned
up during XCloseDisplay before the cairo CloseDisplay hook goes on to
call into XRenderFreePicture.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/cairo-xlib-display.c b/src/cairo-xlib-display.c
index c7c3c43c..b8f35cb8 100644
--- a/src/cairo-xlib-display.c
+++ b/src/cairo-xlib-display.c
@@ -226,6 +226,7 @@ _cairo_xlib_display_get (Display *dpy)
     cairo_xlib_display_t *display;
     cairo_xlib_display_t **prev;
     XExtCodes *codes;
+    int major_unused, minor_unused;
 
     /* There is an apparent deadlock between this mutex and the
      * mutex for the display, but it's actually safe. For the
@@ -260,6 +261,14 @@ _cairo_xlib_display_get (Display *dpy)
     if (display == NULL)
 	goto UNLOCK;
 
+    /* Xlib calls out to the extension close_display hooks in LIFO
+     * order. So we have to ensure that all extensions that we depend
+     * on in our close_display hook are properly initialized before we
+     * add our hook. For now, that means Render, so we call into its
+     * QueryVersion function to ensure it gets initialized.
+     */
+    XRenderQueryVersion (dpy, &major_unused, &minor_unused);
+
     codes = XAddExtension (dpy);
     if (codes == NULL) {
 	free (display);