Failure during CFE_ES_ExitApp if app calls CFE_TBL_Unregister

[pcooksey]

Describe the bug
Should an app call CFE_TBL_Unregister?
On CFE_ES_ExitApp I get:

1980-012-14:03:21.25234 CFE_TBL:RemoveAccessLink-PutPoolBuf[0] Fail Stat=0xC4000007, Hndl=0x56709730, Buf=0x00000000
1980-012-14:03:21.25236 CFE_TBL:RemoveAccessLink-PutPoolBuf[0] Fail Stat=0xC4000007, Hndl=0x56709730, Buf=0x00000000

The documentation no longer says anything about it so I'm starting to think it shouldn't be used. The sample_app in the cFS repo also doesn't call CFE_TBL_Unregister either.

The code seems to say we should though:

cFE/fsw/cfe-core/src/inc/cfe_tbl.h

Lines 334 to 339 in 95f34d2

	** \par Description
	** When an application is being removed from the system, it should
	** unregister those tables that it created. The application should
	** call this function as a part of its cleanup process. The table
	** will be removed from memory once all table addresses referencing
	** it have been released.

To Reproduce

1. Register table
2. Unregister table
3. Call CFE_ES_ExitApp

Expected behavior
No errors on exit

Code snips
N/A

System observed on:

• Hardware: Laptop
• OS: Linux
• Versions: Versions:cFE 6.7.7.0, OSAL 5.0.6.0, PSP 1.4.4.0

Additional context
N/A

Reporter Info
Philip Cooksey, NASA Ames

[pcooksey]

It seems by default the tables are being cleaned up automatically as shown below which is part of the CFE_ES_CleanUpApp function:

cFE/fsw/cfe-core/src/es/cfe_es_apps.c

Lines 1083 to 1085 in d217ca3

	#ifndef EXCLUDE_CFE_TBL
	CFE_TBL_CleanUpApp(AppId);
	#endif

This clean up call eventually calls:

cFE/fsw/cfe-core/src/tbl/cfe_tbl_internal.c

Line 1429 in 95f34d2

CFE_TBL_RemoveAccessLink(i);

Which is the same function in CFE_TBL_Unregister:

cFE/fsw/cfe-core/src/tbl/cfe_tbl_api.c

Line 641 in d217ca3

CFE_TBL_RemoveAccessLink(TblHandle);

Seems like a bug since an already unregistered table shouldn't be cleaned up again by CFE_ES_CleanUpApp -> CFE_TBL_CleanUpApp.

[skliper]

Seems like a bug since an already unregistered table shouldn't be cleaned up again by CFE_ES_CleanUpApp -> CFE_TBL_CleanUpApp.

Agreed. Updated title and marked as bug.

[jphickey]

Tested this today - It may have been fixed by other changes, possibly the transition to ES background task and the better locking ES that was implemented with that.

To test - what I did was modify SAMPLE_APP (which registers a table) to only run for 5 seconds, then exit. As part of exiting, I added a call to CFE_TBL_Unregister() before it calls CFE_ES_ExitApp() ... I confirmed that the first call to CFE_TBL_Unregister is indeed doing the un-registration, followed by ES invoking CFE_TBL_CleanUpApp() via the background task - which did nothing in my test.

The only (minor) issue I observed is that there is an extra "unknown state" event after the app exits itself:
EVS Port1 66/1/CFE_ES 48: ES_ProcControlReq: Unknown State Application SAMPLE_APP ( 1 )

But otherwise everything seemed to work just fine.

[jphickey]

@pcooksey can you check if this issue still exists in the current main branch?

[skliper]

If it's fixed we should still fix the documentation, table will be unregistered during cleanup so this is only needed if the App wants to unregister explicitly.