From owner-cvs-all  Mon May 17  9:48: 6 1999
Delivered-To: cvs-all@freebsd.org
Received: from lor.watermarkgroup.com (lor.watermarkgroup.com [207.202.73.33])
	by hub.freebsd.org (Postfix) with ESMTP
	id BD7F115101; Mon, 17 May 1999 09:47:59 -0700 (PDT)
	(envelope-from luoqi@watermarkgroup.com)
Received: (from luoqi@localhost)
	by lor.watermarkgroup.com (8.8.8/8.8.8) id MAA19874;
	Mon, 17 May 1999 12:47:52 -0400 (EDT)
	(envelope-from luoqi)
Date: Mon, 17 May 1999 12:47:52 -0400 (EDT)
From: Luoqi Chen <luoqi@watermarkgroup.com>
Message-Id: <199905171647.MAA19874@lor.watermarkgroup.com>
To: peter@netplex.com.au
Subject: Re: cvs commit: src/sbin/savecore savecore.c
Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org
Sender: owner-cvs-all@FreeBSD.ORG
Precedence: bulk

> Luoqi Chen wrote:
> > luoqi       1999/05/12 21:29:13 PDT
> > 
> >   Modified files:
> >     sbin/savecore        savecore.c 
> >   Log:
> >   Read dumpdev using sysctl(3) interface. Now savecore should work again
> >   after the dev_t changes.
> 
> I looked at this before and was tempted to do the same, but there is a
> problem..  Using the sysctl() requires that the kernel that crashed is the
> current running kernel.
> 
> For example, if you do a 'make install', then your running /kernel gets
> moved to /kernel.old.  If you defer the shutdown because it's inconvenient,
> and some time later you have a crash and dump, then when you reboot, you
> can't do a savecore unless you first boot from kernel.old.  Previously you
> would just do a 'savecore -N /kernel.old /var/crash' and it would save the
> crashdump and kernel.old as vm(unix|core).nnn.
> 
> I think it would be better to either have a seperate udumpdev, or save the
> pathname string, or look up dumpdev->udev or whatever.  (I have been rather
> busy for the last few days though and have not had time to try it myself
> yet.  The ISP that has been giving me free connectivity in return for
> advice and help is moving to a new building)
> 
> Cheers,
> -Peter
> 
savecore *always* gets dumpdev (and some other variables) from the live kernel,
this makes sense because the value of dumpdev (in .data section of kernel) will
be overwritten after a reboot.

-lq


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe cvs-all" in the body of the message