[omniORB] Unbalanced POA_ptr reference counting in POA_tie class templates

[Mauron, Beat (CH - MSS)]

Hi,

Can you give more details about your suggested correction (which files or class)
Thanks
Béat

-----Original Message-----
From: Daniel Krügler via omniORB-list [mailto:omniorb-list at omniorb-support.com]
Sent: mardi 14 février 2017 08:54
To: omniorb-list at omniorb-support.com
Subject: [omniORB] Unbalanced POA_ptr reference counting in POA_tie class templates

Hi,

We recently tried to use the OmniOrb generated POA_tie class templates via the so-called delegation-based interface implementation approach by additionally providing an explicit (not-null) POA instance via the corresponding constructor. Since we used that approach we noticed internal OmniOrb assertions during shutdown time (when the POA was destroyed). The analysis of the problem indicated a double-destruction attempt of the POA.

By comparing the C++03 CORBA language binding specification of the tie class with the OmniOrb implementation we noticed a seemingly incorrect reference counter balancing in the generated tie classes:

According to the spec, if the implementation internally hold a POA_ptr (Or the equivalent to this), it needs to call POA::_duplicate() in the constructor on the provided POA and in the destructor it needs to call
CORBA::release() on that hosted member. But the current OmniOrb implementation 4.2.1 that we are using, doesn't call POA::_duplicate() in the constructor, but still calls CORBA::release() in the destructor.

As a workaround we have created a derived class for the tie classes that holds another POA_ptr data member were we ensure proper lifetime management as described by the spec, ensuring that we also override the _default_POA() function to return our new member value instead.
>From this point on the shutdown behaviour was normal again, so I would recommend to apply a corresponding fix (That is: Adding the missing
POA::_duplicate() in both constructors accepting a POA) to the code generation of the POA_tie classes ensuring a properly balanced POA reference counting internally.

Thanks,

- Daniel

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