mi: only process master if the SD is still attached.

SDs may be detached during event processing (e.g. if a passive grab
activates). In this case, the event must not be processed through the master
device.

Reported-by: Thomas Jaeger
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

mi/mieq.c

@@ -402,7 +402,9 @@ mieqProcessDeviceEvent(DeviceIntPtr dev,
             /* process slave first, then master */
             dev->public.processInputProc(event, dev);
 
-            if (master)
+            /* Check for the SD's master in case the device got detached
+             * during event processing */
+            if (master && dev->u.master)
                 master->public.processInputProc(
                         (InternalEvent*)masterEvents->event,
                         master);