Here is a better description of the problem and a possible fix that Vlad
can use and discard, as he surely better understand this part.
Sorry for some imprecision in my previous description.
Jaybird synchronized the op_queue_events send/response.
Remote queue_events synchronizes with the *sync* port lock.
When event callback is called by the engine, before delivery the event,
remote marks it as dead (event->rvnt_iface = NULL) but using the *async*
port lock.
Even the different locks (sync / async) is not the underling problem by
the way events are marked and verified as dead.
But after event is marked as dead, que_events can concurrently reuse it,
and reuse its rvnt_id.
The problem is that the callback reads rvnt_id after mark it as dead.
So here is my proposed patch.
Adriano
diff --git a/src/remote/server/server.cpp b/src/remote/server/server.cpp
index 8c5662e..e5bb59c 100644
--- a/src/remote/server/server.cpp
+++ b/src/remote/server/server.cpp
@@ -917,6 +917,8 @@ public:
if (!allowCancel)
return;
+ SLONG rvnt_id = event->rvnt_id;
+
if (event->rvnt_iface)
{
LocalStatus ls;
@@ -934,7 +936,7 @@ public:
p_event->p_event_database = rdb->rdb_id;
p_event->p_event_items.cstr_length = length;
p_event->p_event_items.cstr_address = items;
- p_event->p_event_rid = event->rvnt_id;
+ p_event->p_event_rid = rvnt_id;
port->send(&packet);
}
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