memory: unregister AddressSpace MemoryListener within BQL

address_space_destroy_dispatch is called from an RCU callback and hence
outside the iothread mutex (BQL).  However, after address_space_destroy
no new accesses can hit the destroyed AddressSpace so it is not necessary
to observe changes to the memory map.  Move the memory_listener_unregister
call earlier, to make it thread-safe again.

Reported-by: Alex Williamson <alex.williamson@redhat.com>
Fixes: 374f2981d1f10bc4307f250f24b2a7ddb9b14be0
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/memory.c b/memory.c
index 9b91243..130152c 100644
--- a/memory.c
+++ b/memory.c
@@ -1978,6 +1978,7 @@ void address_space_destroy(AddressSpace *as)
     as->root = NULL;
     memory_region_transaction_commit();
     QTAILQ_REMOVE(&address_spaces, as, address_spaces_link);
+    address_space_unregister(as);
 
     /* At this point, as->dispatch and as->current_map are dummy
      * entries that the guest should never use.  Wait for the old