Re: MemoryContextAlloc: invalid request size 1934906735

On August 28, 2002 09:23 am, Tom Lane wrote:

> The behavior looks a lot like a memory clobber, so perhaps the key
> variable is some difference in malloc's allocation strategy, causing
> two items to be adjacent in NetBSD where they are not on the other
> platforms we've tried.

Hmm. I might try adding some buffer in MemoryContextAlloc() and see if that
changes anything. One thing that may be different is that NetBSD is 64 bit
clean. I don't think the other i386 systems are.

> I eyeballed the chkpass code and didn't see any sign of buffer overruns,
> but maybe it needs a harder look.

It's pretty simple. Not even indexing. In fact, I wondered if I should add
some just like my other type that does do indexing. That seemed to be the
only real difference between the two and the other works.

> Hm --- I guess another possible variable is behavior of the local
> crypt() function. Is NetBSD's crypt perhaps willing to return strings
> longer than 13 chars?

Well, the value that it stores is the correct 13 character DES string.

> Did you try CVS tip both with and without --enable-cassert? That turns
> on memory context checking which might alter the failure in interesting
> ways.

No difference. It seems that PostgreSQL is too good at catching the problem
before the assert macros see it.

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