c907bca Ticket 49780 - acl_copyEval_context double free

Authored and Committed by lkrispen 3 years ago
    Ticket 49780 - acl_copyEval_context double free
    Bug: There is a connection an operation extension to keep evaluation
         results cached across multiple operations.
         In the geteffective for each evaluation a sepatate temporary connection
         extension is created and freed. If there are several concurrent operations
         in one connection the operation extension destructor can try to access
         an already freed connection extension.
    Fix: Do not free the connectcion extension during the life time of a
         connection. If a temporary extension should be used, lock the connection extension,
         copy the content  to a saved structure and copy the temporary data to the
         connection extension. When done with the temporary extension reverse this.
         To make this work the locks need to be directly created, the use of the limited
         preallocated array of locks could lead to a situation where both the main and
         the temporary extension would get the sam elock assigned.
    Reviewed by: Thierry and Mark, Thanks