Path: utzoo!attcan!utgpu!watmath!watdragon!rose!sjorr
From: sjorr@rose.waterloo.edu (Stephen Orr)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Catching free memory violations
Message-ID: <15515@watdragon.waterloo.edu>
Date: 30 Jul 89 14:18:04 GMT
References: <7408@ecsvax.UUCP> <694@jc3b21.UUCP> <SHADOW.89Jul29071247@pawl.rpi.edu>
Sender: daemon@watdragon.waterloo.edu
Reply-To: sjorr@rose.waterloo.edu (Stephen Orr)
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Organization: U. of Waterloo, Ontario
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>                          ....  The idea was to SetFunction() the
>FreeMem() function to zero memory *as it is freed*.  Then either a
>SetFunction()ed AllocMem() function or some separate task/function
>could check the free list to make sure it is zeroed.  If not, it is a
>sign of corruption.

	One thing to watch for, zeroing the memory chunk may not be 
enough, when the OS coallesces free chunks it probably leaves the old 
forward pointer alone, and this could appear as 'corrupted memory' unless
the coallesce is done one the fly just 'expanding' an existing free memory
chunk, I'm not sure, but this is to be considered.

				Stephen Orr


{ The opinions expressed herin ARE those of my employer...
		I'm self employed !		- Stephen Orr	}
>--
>Deven T. Corzine        Internet:  deven@rpi.edu, shadow@pawl.rpi.edu