libdbusmenu crashes in prop_array_teardown

It is possible that this issue has the same cause as the #837009. I am not sure about it, so I am creating another one.

I have attached a stack trace. The problem is in prop_array. On widow closing, in my particular case functions are invoked in the next order

1. Check in menuitem_property_idle that priv->prop_array is not NULL
2. Entering dbusmenu_server_dispose
3. Deallocation of priv->prop_array and assigning NULL to it
3. Exiting dbusmenu_server_dispose
4. Entering dbusmenu_server_finalize
5. Exiting dbusmenu_server_finalize
6. Invoking prop_array_teardown that accesses priv->prop_array->len which has been deallocated in #3

As a simple fix I would think about checking of the array for NULL in the beginning of prop_array_teardown. But I found that in my case the prop array is invoked from different threads (I used (pid_t) syscall (SYS_gettid) to compare the thread ids). By this reason, it seems the code needs better synchronization.

Please let me know if I can disable multithreading for the library or may be I use libdbusmenu incorrectly.

Actually the problem happens in Intellij IDEA when I am trying to use Jayatana library which is written on top of Ayatana library. This issue is a stopper for using Unity menu.

My environment is Ubuntu 13.04

I can provide a dump as well.