[omniORB] Memory Leak (CosNaming::NamingContextExt::_narrow)

Mifflin Mabalot mf051404 at yahoo.com
Wed Dec 11 07:10:52 GMT 2013 

Hi Duncan,

Then if invocations on the new
location fail, omniORB retries with the original object reference.
That's important for various implementation repository approaches and
for object migration support.

>> What happens if invocations on the new location succeed? Is the original object reference "deallocated", I think this is what's missing

I am using VC++ VS2010 (omniORB version is 4.1.7 compiled using cygwin using VS10 configurations)
It's probably better to provide code snippets and the trace log, so you can visualize easily:
Code Snippet:
DECLARATIONS:
helloInterface::HelloInt_varm_HelloObj;
CORBA::String_varm_ObjName;
CORBA::Object_varm_ObjContext;
CosNaming::NamingContextExt_varm_RootContext;
CORBA::Object_varm_NSObj;
CORBA::ORB_varm_ORB;

INITIALIZATION snippet:
//initialize ORB
CString lstr_Opt1 = "-ORBInitRef";
CString lstr_NS = "NameService=" + TaskWork.m_CORBAURL;
CString lstr_Opt2 = "-ORBDefaultInitRef";
CString lstr_NSDefault = TaskWork.m_CORBAURL + "#services" ;
//char *lc_argv[] = {lstr_Opt1.GetBuffer(), lstr_NS.GetBuffer(), lstr_Opt2.GetBuffer(), lstr_NSDefault.GetBuffer()} ;
char *lc_argv[] = {lstr_Opt1.GetBuffer(), lstr_NS.GetBuffer()} ;
int li_argc = (int)(sizeof(lc_argv)/sizeof(lc_argv[ 0 ]));

const char* options[][2] = {
{ "traceLevel", "11" }, 
{ "traceExceptions", "1" }, 
{ "traceInvocationReturns", "1" }, 
{ "offerBiDirectionalGIOP", "1" }, 
{ "nativeCharCodeSet", "UTF-8" }, 
{ NULL, NULL }
   };    
TaskWork.m_ORB = CORBA::ORB_init(li_argc, lc_argv, "omniORB4", options);
omniORB::installSystemExceptionHandler(NULL,&CTask_CORBAClientDriver::ExceptionHandler);
omniORB::installTransientExceptionHandler(NULL,&CTask_CORBAClientDriver::TransientHandler);
omniORB::installCommFailureExceptionHandler(NULL,&CTask_CORBAClientDriver::CommExceptionHandler);
omniORB::setLogFunction(&CTask_CORBAClientDriver::omniOrbLog);

METHOD snippet:
TaskWork.m_NSObj = TaskWork.m_ORB->resolve_initial_references("NameService");
TaskWork.m_RootContext = CosNaming::NamingContextExt::_narrow(TaskWork.m_NSObj);
if(CORBA::is_nil(TaskWork.m_RootContext)){
CLogOut::OutputCORBALog("Naming Context ERROR"); 
} else {
TaskWork.m_ObjContext = TaskWork.m_RootContext->resolve_str(TaskWork.m_ObjName);
//Get and store the remote obj
if (!CORBA::is_nil(TaskWork.m_ObjContext)) {
TaskWork.m_HelloObj = helloInterface::HelloInt::_narrow(TaskWork.m_ObjContext);
if (!CORBA::is_nil(TaskWork.m_HelloObj)) {
Log.Format( "Remote Object Found: %s [%s]", TaskWork.m_CORBAURL, TaskWork.m_CORBAObjName);
CLogOut::OutputCORBALog( Log );
}
}
}

omniORB Tracer log (custom logger set by using: omniORB::setLogFunction)
[2013/12/10 17:48:47.069] [omniORB TRACE] : omniORB: Creating ref to remote: key<NameService>. target id      : IDL:omg.org/CORBA/Object:1.0. most derived id: .
[2013/12/10 17:48:47.069] [omniORB TRACE] : omniORB: Initial reference `NameService' resolved from -ORBInitRef argument / ORB registration..
[2013/12/10 17:48:47.070] [omniORB TRACE] : omniORB: AsyncInvoker: thread id = 1 has started. Total threads = 1.
[2013/12/10 17:48:47.519] [omniORB TRACE] : omniORB: Creating ref to remote: key<ｯｫﾋ.......B.................RootPOA.....TNameService.................>. target id      : IDL:omg.org/CORBA/Object:1.0. most derived id: IDL:omg.org/CosNaming/NamingContextExt:1.0.
[2013/12/10 17:48:47.519] [omniORB TRACE] : omniORB: Finish '_is_a' (location forward).
[2013/12/10 17:48:47.520] [omniORB TRACE] : omniORB: GIOP::LOCATION_FORWARD -- retry request..
[2013/12/10 17:48:47.523] [omniORB TRACE] : omniORB: Return '_is_a' on remote: key<ｯｫﾋ.......B.................RootPOA.....TNameService.................>.
[2013/12/10 17:48:47.523] [omniORB TRACE] : omniORB: Creating ref to remote: key<ｯｫﾋ.......B.................RootPOA.....TNameService.................>. target id      : IDL:omg.org/CosNaming/NamingContextExt:1.0. most derived id: .
[2013/12/10 17:48:47.524] [omniORB TRACE] : omniORB: Creating ref to remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>. target id      : IDL:omg.org/CORBA/Object:1.0. most derived id: RMI:helloInterface.HelloInt:0000000000000000.
[2013/12/10 17:48:47.525] [omniORB TRACE] : omniORB: Return 'resolve_str' on remote: key<ｯｫﾋ.......B.................RootPOA.....TNameService.................>.
[2013/12/10 17:48:47.525] Remote Object Found: corbaname::localhost:1055 [HelloIIOP]
[2013/12/10 17:48:47.525] [omniORB TRACE] : omniORB: LocateRequest to remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>.
[2013/12/10 17:48:47.528] [omniORB TRACE] : omniORB: Return 'sayHello' on remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>.
[2013/12/10 17:48:47.529]      Remote Object Return Value : Hello World
[2013/12/10 17:48:48.414] [omniORB TRACE] : omniORB: Return 'sayHello' on remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>.
[2013/12/10 17:48:48.414]      Remote Object Return Value : Hello World
[2013/12/10 17:48:49.398] [omniORB TRACE] : omniORB: Return 'sayHello' on remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>.
[2013/12/10 17:48:49.398]      Remote Object Return Value : Hello World
[2013/12/10 17:48:50.397] [omniORB TRACE] : omniORB: Return 'sayHello' on remote: key<ｯｫﾋ.....ﾚ.ﾀ..............>.
[2013/12/10 17:48:50.397]      Remote Object Return Value : Hello World
[2013/12/10 17:48:50.668] [omniORB TRACE] : omniORB: Preparing to shutdown ORB..
[2013/12/10 17:48:50.669] [omniORB TRACE] : omniORB: Shutting-down all incoming endpoints..
[2013/12/10 17:48:50.669] [omniORB TRACE] : omniORB: ORB shutdown is complete..
[2013/12/10 17:48:50.669] [omniORB TRACE] : omniORB: Deinitialising omniDynamic library..
[2013/12/10 17:48:50.670] [omniORB TRACE] : omniORB: AsyncInvoker: thread id = 1 has exited. Total threads = 1.
[2013/12/10 17:48:50.670] [omniORB TRACE] : omniORB: AsyncInvoker: deleted..
[2013/12/10 17:48:50.670] CORBA Object Closed...
[2013/12/10 17:48:50.670] ORB Destroyed...

Visual Studio 2010 partial output log indicating the leak:
Detected memory leaks!
Dumping objects ->
{55607} normal block at 0x00B1E300, 100 bytes long.
 Data: <@ﾆ>[ Ww         > 40 C6 3E 5B 20 57 77 00 FF FF FF FF 00 00 00 00 
Object dump complete.

Other notes:
Whenever a remote object is referenced, that too is causing leaks, but I found a way to cleanup the leaks by incorporating some extra code, see below (maybe the "allocation for every reference" is by design and is included in the CORBA specs, but I used a _var (smart pointer) which has been discussed as "self-cleaning / self-deallocating" during destruction, yet it is leaving behind leaks)
  CString* lClientRequest = (CString*)RecvParam.m_pPtr; 
if (!TaskWork.m_ORB->_NP_is_nil() && !TaskWork.m_ORB->_non_existent() && !TaskWork.m_HelloObj->_is_nil()) {
// Get the object's "storage location" so you can free it later (every time it is "referenced" a new allocation is made)
CORBA::WStringValue* l_sayHelloPtr = TaskWork.m_HelloObj->sayHello();
// Process all you want
*lClientRequest = l_sayHelloPtr->_boxed_out();
CString Log;
Log.Format( "     Remote Object Return Value : %s", *lClientRequest);
CLogOut::OutputCORBALog( Log );
// Cleanup to avoid leaks (this simply releases a reference, so that the object can clean/deallocate itself)
CORBA::WStringValue_Helper::remove_ref(l_sayHelloPtr); // >> NOT DOING THIS WILL CAUSE LEAKS
}

If you need anything else please let me know.  Hope you can shed light on what am I doing wrong, or if indeed this is a bug (we can currently tolerate this as it is just causing a 100-byte leak, but leak is a leak, we want code which 100% clean).  Thanks!

Regards,
Miff



On Wednesday, December 11, 2013 6:48 AM, Duncan Grisby <duncan at grisby.org> wrote:
 
On Tue, 2013-12-10 at 18:38 +0800, Mifflin Mabalot wrote:
>
>
>> I think there is a bug on CosNaming::NamingContextExt::_narrow.  When
>> an omniORB::LOCATION_FORWARD happens, the initially allocated object
>> gets orphaned when trying to do a "GIOP::LOCATION_FORWARD -- retry
>> request.."  I think cleanup of the initially allocated object should
>> be done inside omni::locationForward()
>
>What exactly are the circumstances, and what makes you think there is a
>leak?
>
>By design, when an invocation returns with a location forward, omniORB
>remembers the original object reference. Then if invocations on the new
>location fail, omniORB retries with the original object reference.
>That's important for various implementation repository approaches and
>for object migration support.
>
>Duncan.
>
>-- 
>-- Duncan Grisby         --
>  -- duncan at grisby.org     --
>   -- http://www.grisby.org 
>--
>
>
>
>
>
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