Date: Wed, 2 Feb 2011 21:07:03 -0500
From: Vivek Goyal <vgoyal@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        linux kernel mailing list <linux-kernel@vger.kernel.org>,
        Jarod Wilson <jwilson@redhat.com>, akpm@linux-foundation.org
Subject: Re: [Patch] kexec: remove KMSG_DUMP_KEXEC (was Re: Query about
 kdump_msg hook into crash_kexec())
Message-ID: <20110203020703.GB21603@redhat.com>
References: <20110201073853.GB21239@cr0.nay.redhat.com>
 <20110201081313.GC21239@cr0.nay.redhat.com>
 <20110203095837.93A2.A69D9226@jp.fujitsu.com>
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On Thu, Feb 03, 2011 at 09:59:04AM +0900, KOSAKI Motohiro wrote:
> > On Tue, Feb 01, 2011 at 03:38:53PM +0800, Am?rico Wang wrote:
> > >On Mon, Jan 31, 2011 at 11:33:15PM -0800, Eric W. Biederman wrote:
> > >>The issue is the inane call inside crash_kexec.
> > >>
> > >>It requires both a kexec kernel to be loaded and it requires you to be
> > >>crashing.  Given that when I audited the kmsg_dump handlers they really
> > >>weren't safe in a crash dump scenario we should just remove it.
> > >>
> > >
> > >Probably, I think we need to get rid of KMSG_DUMP_KEXEC.
> > >
> > 
> > Here we go.
> > 
> > --------->
> > 
> > KMSG_DUMP_KEXEC is useless because we already save kernel messages
> > inside /proc/vmcore, and it is unsafe to allow modules to do
> > other stuffs in a crash dump scenario.
> > 
> > Reported-by: Vivek Goyal <vgoyal@redhat.com>
> > Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> > Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
> 
> I wrote why this is no good idea by another mail. Please see it.
> Anyway you have a right to don't use this feature.
> 

But you have not explained that why do you need to hook into crash_kexec()
and you have also not explained why do you need to send out kdump_msg()
notification if kdump is configured.

Some detailed explanation here would help.

Thanks
Vivek

> Nack.
> 
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