[Python-Dev] tp_dealloc

[smarv at gmx.net]

> This said, there may be a bug somewhere, but what do you want us to look
> at?
> Do you have a case that we could reproduce and investigate?
> 
> -- 
> Amaury Forgeot d'Arc

Thank you, I'm not a C-Developer, 
but still I have one more detail:

I call py_decRef( pyObj) of dll (version 3.1.1), 
( which calls tp_dealloc, which calls my freeMem() method))
No problem is reported here.
Now, the freed memory should not be accessed anymore by python31.dll. 
You may fill the freed pyObjectHead with invalid values, 
in my case it's:  ob_refcnt= 7851148, ob_type = $80808080 

But later, when I call Py_Finalize, 
there inside is some access to the same freed memory; 
this causes an AV, more precisely, 
when the value $80808080 is checked.

My Delphi-Debugger shows the following byte-sequence inside python31.dll:
5EC3568B7424088B4604F74054004000007504

5E                  - pop esi
C3                  - ret    
56                  - push esi
8B742408            - mov esi, [esp+$08]
8B4604              - mov eax, [esi+$04]  
       // eax = $80808080 //

F7405400400000      - test [eax+$54], $00004000 
       // AV exception by read of address $808080D4 // 

7504                - jnz $1e03681b


Maybe this can help someone, thank you!

-- 
Marvin

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