linux-kernel - RE: [PATCH] printk: fixing the deadlock when calling printk in nmi handle

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Date:	Wed, 04 Jul 2012 16:12:51 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Liu, Chuansheng" <chuansheng.liu@...el.com>
Cc:	"'linux-kernel@...r.kernel.org' (linux-kernel@...r.kernel.org)" 
	<linux-kernel@...r.kernel.org>, "kay@...y.org" <kay@...y.org>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"mingo@...e.hu" <mingo@...e.hu>
Subject: RE: [PATCH] printk: fixing the deadlock when calling printk in nmi
 handle

On Wed, 2012-07-04 at 16:09 +0200, Peter Zijlstra wrote:
> On Wed, 2012-07-04 at 15:39 +0200, Peter Zijlstra wrote:
> > > Anyway, in nmi handler, calling printk is dangerous. This patch is for this case.
> > 
> > But its ugly and decreases reliability..  Your 'solution' is to
> > basically ignore serialization and pray, that's not a solution, that's
> > gambling. 
> 
> If you want to fix it, do something like:
> 
>   http://marc.info/?l=linux-kernel&m=132446646923333


Note that the one 'down' side of this is that the folks who care about
logbuf content might get upset since we don't put all msgs in there
anymore.

These would be the kmsg_dump users..



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