Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752503AbaKFQ4X (ORCPT ); Thu, 6 Nov 2014 11:56:23 -0500 Received: from cantor2.suse.de ([195.135.220.15]:57686 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247AbaKFQ4U (ORCPT ); Thu, 6 Nov 2014 11:56:20 -0500 Date: Thu, 6 Nov 2014 17:56:17 +0100 From: Petr Mladek To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Jiri Kosina , "H. Peter Anvin" , Thomas Gleixner , "Paul E. McKenney" Subject: Re: [RFC][PATCH 11/12 v3] printk: Add per_cpu printk func to allow printk to be diverted Message-ID: <20141106165617.GA28294@dhcp128.suse.cz> References: <20141104155237.228431433@goodmis.org> <20141104160223.146433028@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141104160223.146433028@goodmis.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 2014-11-04 10:52:48, Steven Rostedt wrote: > From: "Steven Rostedt (Red Hat)" > > Being able to divert printk to call another function besides the normal > logging is useful for such things like NMI handling. If some functions > are to be called from NMI that does printk() it is possible to lock up > the box if the nmi handler triggers when another printk is happening. > > One example of this use is to perform a stack trace on all CPUs via NMI. > But if the NMI is to do the printk() it can cause the system to lock up. > By allowing the printk to be diverted to another function that can safely > record the printk output and then print it when it in a safe context > then NMIs will be safe to call these functions like show_regs(). > > Link: http://lkml.kernel.org/p/20140619213952.209176403@goodmis.org > > Acked-by: Paul E. McKenney > Signed-off-by: Steven Rostedt Looks fine to me. Reviewed-by: Petr Mladek Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/