From owner-freebsd-current  Sat Oct  7 20: 7:10 2000
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Date: Sat, 7 Oct 2000 23:06:55 -0400 (EDT)
From: "Marc G. Fournier" <scrappy@hub.org>
To: Bosko Milekic <bmilekic@dsuper.net>
Cc: gibbs@FreeBSD.ORG, freebsd-current@FreeBSD.ORG
Subject: Re: latest ahc panic, more data ...
In-Reply-To: <Pine.BSF.4.21.0010072233400.285-100000@jehovah.technokratis.com>
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there is a thread going on in committers that appears to revolve aroudn
this issue, and Justin has been throwing out patches, so it is being
worked on "fast and furious" ... I'm currently up in Windows (Dual-Boot
machine fo rmy little girl) watching for a physical commit to the
repository that at least suggestions its a fix before rebooting and
upgrading :)


On Sat, 7 Oct 2000, Bosko Milekic wrote:

> 
>   I've just been hit by one such problem on bootup. This is -current as of
>   today, so I suspect it's the commits that went in the past two days.
> 
>   Basically, I tracked it down just enough to know that the problem is
>   happening during a call to ahc_print_path() in aic7xxx.c, specifically
>   for me, this happens during bootup in ahc_handle_scsiint() right after
>   the second call to ahc_abort_scbs().
> 
>   ahc_print_path() is called like this:
> 
>   	ahc_print_path(ahc, scb);
> 
> 	(why both ahc and scb are being passed, I have no idea, since
> 	ahc_print_path only actually makes use of scb).
> 
>   For the unaware, ahc_print_path() seems to only wrap a call to
>   xpt_print_path() to which it passes scb->io_ctx->ccb_h.path as an
>   argument, and in this case, scb->io_ctx happens to be NULL, so during its
>   pass, a NULL pointer gets dereferenced and the page fault happens.
> 
>   The NULLing out of this is coming somewhere in ahc_handle_scsiint(),
>   because some prior ahc_print_path()s (with the same arguments) are
>   succeeding.
> 
>   I have not tried backing out the changes from the past two days and
>   trying again, but this was not happening a week ago.
> 
>   So what's going on here?
> 
> On Sat, 7 Oct 2000, Marc G. Fournier wrote:
> 
> > 
> > okay, have been watching the conversation going on in the committers list,
> > and am watching for any new commits that seem appropriate, but figure
> > adding a little bit of extra info as I come up with it might help?
> > 
> > latest reboot had a bit more info then the last, and started with:
> > 
> > ahc0:A:1: ahc_intr - referenced scb not valid during seqint 0x73 scb(147)
> > ach0: WARNING no command for scb 147 (cmdcmplt)
> > QOUTPOS=132
> > 
> > Marc G. Fournier                               scrappy@hub.org
> > Systems Administrator @ hub.org                    
> > scrappy@{postgresql|isc}.org                       ICQ#7615664
> 
> 
> 
>   Bosko Milekic
>   bmilekic@technokratis.com
> 
> 
> 
> 
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> 

Marc G. Fournier                               scrappy@hub.org
Systems Administrator @ hub.org                    
scrappy@{postgresql|isc}.org                       ICQ#7615664



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