From: MenTaLguY <mental@...>
Date: 2007-01-16T00:28:09+09:00
Subject: Re: building Ruby with dmalloc

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On Sat, 2007-01-13 at 10:13 +0900, Young Hyun wrote:

> The invalid values in fastthread's mutex object is similar to what =20
> we've seen in the 2nd type of crash ("rb_gc_mark(): unknown data =20
> type").  I'll try to create a test program to reproduce this crash at =20
> exit, and since the corruption appears similar, this test program =20
> should hopefully be useful for diagnosing the 2nd type of crash as well.

I believe the two crashes are related.  Also, it appears that the
corruption only happens with Queues, not other uses of Mutexes.  Likely
this means that some queue-specific routine expecting a queue is getting
passed a pointer to a member of the queue instead, or a routine
expecting one member is getting passed another.

I'd expect the compiler to catch this sort of thing, and I didn't see
anything obvious auditing the code by hand, but perhaps something's
getting lost in a VALUE cast...

Anyway, it's probably best to focus on Queue when constructing test
cases.

-mental

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