From owner-freebsd-bugs  Mon May 20 13: 0:32 2002
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Date: Mon, 20 May 2002 13:00:08 -0700 (PDT)
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From: Andrew Gallatin <gallatin@cs.duke.edu>
Subject: Re: kern/37060
Reply-To: Andrew Gallatin <gallatin@cs.duke.edu>
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The following reply was made to PR kern/37060; it has been noted by GNATS.

From: Andrew Gallatin <gallatin@cs.duke.edu>
To: Matthias Andree <matthias.andree@stud.uni-dortmund.de>
Cc: matthias.andree@web.de, freebsd-gnats-submit@freebsd.org,
	sos@freebsd.org
Subject: Re: kern/37060
Date: Mon, 20 May 2002 15:53:15 -0400 (EDT)

 Matthias Andree writes:
  > On Mon, 20 May 2002, Andrew Gallatin wrote:
  > 
  > > >It would be helpful to know which pointer was null.  There
  > > >are many of them on line 710 of ata-disk.c
  > 
  > Ok, it looks as though bad things happen when the non-existant primary
  > slave is probed. I used boot -dg, set a breakpoint at ad_service and
  > after successfully detecting the first drive, I got some info.
  > 
  > The most important lines from below, consistent with the trap
  > (ATA_DEV(ATA_SLAVE) == 1):
  > 
  > (kgdb) print ((struct ad_softc *)(adp->device->channel->device[1].driver))
  > $9 = (struct ad_softc *) 0x0
  > 
  > So the problem happens probably at line #713 when dereferencing
  > ->flags.
 
 
 What if you protect those access with a check for a non-null driver?
 
 Also, what happens if you comment out the call to the
 ata_raiddisk_attach() in ad_attach() ?
 
 Drew
 
 

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