Re: [Patch] kexec: remove KMSG_DUMP_KEXEC (was Re: Query about kdump_msg hook into crash_kexec())

From: KOSAKI Motohiro
Date: Wed Feb 02 2011 - 19:59:14 EST


> On Tue, Feb 01, 2011 at 03:38:53PM +0800, AmÃrico 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@xxxxxxxxxx>
> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> Signed-off-by: WANG Cong <xiyou.wangcong@xxxxxxxxx>

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.

Nack.


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