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Date: Mon, 15 Jan 1996 00:13:06 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199601141313.AAA05940@godzilla.zeta.org.au>
To: freebsd-hackers@freefall.freebsd.org, garyj@munich.netsurf.de
Subject: Re: Status of ISDN drivers
Cc: isdn@muc.ditec.de
Sender: owner-hackers@FreeBSD.ORG
Precedence: bulk

>I've become aware of a horrible bug somewhere in the ISDN code in the
>last few days which apparently trashes the kernel stack somehow.

Someone actually uses the isdn drivers in FreeBSD? :-)  Perhaps they
have been broken by recent cleanups.  OTOH, perhaps they have been
fixed by recent cleanups.  What version are you using?

>This bug is extrememly hard to track down beacuse the fault address is
>totally bogus, e.g. 8:0. That's why I suspect that the stack is getting
>trashed. It also crops up under circumstances which I can't identify.

This fault address (but not a trashed stack) is normal for a call or
jump through a null pointer.  Calls through null pointers are very
easy to debug since the return address is on the stack, while jumps
through null pointers are hard to debug.

Bruce