From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752243AbbFVSPr (ORCPT ); Mon, 22 Jun 2015 14:15:47 -0400 Received: from mail.skyhub.de ([78.46.96.112]:60999 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906AbbFVSPj (ORCPT ); Mon, 22 Jun 2015 14:15:39 -0400 Date: Mon, 22 Jun 2015 20:15:28 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: Kees Cook , "Paul E. McKenney" , "linux-kernel@vger.kernel.org" , Oleg Nesterov , Denys Vlasenko , Brian Gerst , =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker , X86 ML , Rik van Riel Subject: Re: [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify_die Message-ID: <20150622181528.GE20244@pd.tnic> References: <20150622113649.GB20244@pd.tnic> <20150622163333.GC20244@pd.tnic> <20150622172400.GD20244@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 22, 2015 at 10:37:39AM -0700, Andy Lutomirski wrote: > But if we OOPS, we'll OOPS after the lockdep splat and the lockdep > splat will scroll off the screen, right? Am I missing something here? No, you're not. > notify_die is called before the actual OOPS code is invoked in traps.c. Yes, and with this assertion, you get to potentially print two dump_stack()'s back-to-back instead of the one from traps.c. And if the machine is about to be wedged solid soon anyway, we want to dump as less (not-so-important) blurb to serial/console as possible. And in this case, my suspicion is not that the lockdep splat will scroll off the screen but that we might freeze before we even issue the whole thing. That's why I think we should be conservative and make the lockdep splat come out second, if possible. Am I making more sense now? -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/