443002 - Access violation closing Visual Basic 6 (VB6) project with Mozilla Control

Status: RESOLVED INVALID

(Core Graveyard :: Embedding: ActiveX Wrapper, defect)

Description

[Richard Morrison]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1a1pre) Gecko/2008063003 Minefield/3.1a1pre
Build Identifier: http://releases.mozilla.org/pub/mozilla.org/xulrunner/releases/1.9.0.0/runtimes/xulrunner-1.9.en-US.win32.zip

When closing a Visual Basic 6 project that uses the Mozilla Control, VB6.EXE is shutdown by the OS reporting an error similar to the following:

Unhandled exception at 0x07eb51df in VB6.EXE: 0xC0000005: Access violation reading location 0x07eb51df.

The Designer must be 

Reproducible: Always

Steps to Reproduce:
1. Open VB 6 
2. Add the Mozilla Control component to the project
3. Add a Mozilla Control to Form1's Designer
4. Close VB 6 - saving the project is not required

Alternative steps:
1. Follow steps 1 - 3 above
2. Save the project.
3. Close and ignore error
4. Start VB 6 again.
5. Load project saved in step 2
6. Open the Form1 designer
7. Close VB 6
Actual Results:  
Both set of steps cause an access violation. The first set of steps didn't always cause the error.

The first set of steps produce the following call stack in VS 2005:
>	08013a56()	
 	user32.dll!_InternalCallWinProc@20()  + 0x28 bytes	
 	user32.dll!_UserCallWinProcCheckWow@32()  + 0xb7 bytes	
 	user32.dll!_DispatchClientMessage@20()  + 0x4d bytes	
 	user32.dll!___fnDWORD@4()  + 0x24 bytes	
 	ntdll.dll!_KiUserCallbackDispatcher@12()  + 0x13 bytes	
 	user32.dll!_NtUserDestroyWindow@4()  + 0xc bytes	
 	VB6.EXE!004b539a() 	
 	[Frames below may be incorrect and/or missing, no symbols loaded for VB6.EXE]	
 	uxtheme.dll!_ThemeDefWindowProcA@16()  + 0x18 bytes	
 	user32.dll!__EndUserApiHook@0()  + 0x11 bytes	
 	VB6.EXE!0040389e() 	
 	user32.dll!_InternalCallWinProc@20()  + 0x28 bytes	
 	user32.dll!_UserCallWinProcCheckWow@32()  + 0xb7 bytes	
 	user32.dll!_DispatchClientMessage@20()  + 0x4d bytes	
 	user32.dll!___fnDWORD@4()  + 0x24 bytes	
 	ntdll.dll!_KiUserCallbackDispatcher@12()  + 0x13 bytes	
 	user32.dll!_NtUserMessageCall@28()  + 0xc bytes	
 	user32.dll!_RealDefWindowProcA@16()  + 0x27 bytes	
 	uxtheme.dll!_ThemeDefWindowProc()  + 0x132 bytes	
 	uxtheme.dll!_ThemeDefWindowProcA@16()  + 0x18 bytes	
 	user32.dll!_DefWindowProcA@16()  + 0x11c2f bytes	
 	VB6.EXE!004b548c() 	
 	user32.dll!_CallNextHookEx@16()  + 0x3b bytes	
 	msctf.dll!SysGetMsgProc()  + 0x83 bytes	
 	0013fd54()	
 	user32.dll!_InternalCallWinProc@20()  + 0x28 bytes	
 	user32.dll!_UserCallWinProcCheckWow@32()  + 0xb7 bytes	
 	user32.dll!_DispatchMessageWorker@8()  + 0xdc bytes	
 	user32.dll!_DispatchMessageA@4()  + 0xf bytes	
 	VB6.EXE!004828f2() 	
 	VB6.EXE!00482852() 	
 	MSO97RT.DLL!3078d393() 	
 	MSO97RT.DLL!3078d224() 	
 	VB6.EXE!00482809() 	
 	VB6.EXE!0041ee6b() 	
 	VB6.EXE!0041da02() 	
 	kernel32.dll!_BaseProcessStart@4()  + 0x23 bytes	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	
 	VB6.EXE!0057005c() 	


This shorter call stack results from the access violation when closing VB fro the second set of steps:
 	080b51df()	
>	nspr4.dll!_PR_MD_UNLOCK(_MDLock * lock=0x0841b2e0)  Line 347	C
 	nspr4.dll!_PR_NativeRunThread(void * arg=0x08417250)  Line 458	C
 	nspr4.dll!pr_root(void * arg=0x0842f280)  Line 122 + 0xd bytes	C
 	mozcrt19.dll!_callthreadstartex()  Line 348 + 0x9 bytes	C
 	mozcrt19.dll!_threadstartex(void * ptd=0x084b0800)  Line 326 + 0x5 bytes	C
 	kernel32.dll!_BaseThreadStart@8()  + 0x37 bytes	


Expected Results:  
The VB 6 IDE should shutdown without errors. This error doesn't occur when the compiled executable shuts down.

This didn't happen with the Mozilla Control build in XULRunner 1.8.0.4

Comment 1

[Richard Morrison]

Attachment: VB 6 project files

This sample project should save time reproducing the defect.
1. Open the VBP project file
2. Open Form1 Designer
3. Close the VB 6 IDE

This should cause the access violation quickly and easily.

Comment 2

[Ed Morley [:emorley]]

The ActiveX embedding API was removed in bug 662023 and friends, making this INVALID.

[Filter bugspam on activexinvalid]