From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23573C3A589 for ; Wed, 21 Aug 2019 00:50:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB75D22DD6 for ; Wed, 21 Aug 2019 00:50:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726760AbfHUAu2 (ORCPT ); Tue, 20 Aug 2019 20:50:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:60296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726128AbfHUAu1 (ORCPT ); Tue, 20 Aug 2019 20:50:27 -0400 Received: from oasis.local.home (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 542C3206BB; Wed, 21 Aug 2019 00:50:26 +0000 (UTC) Date: Tue, 20 Aug 2019 20:50:20 -0400 From: Steven Rostedt To: Kees Cook Cc: Christophe Leroy , Peter Zijlstra , Andrew Morton , Drew Davenport , Arnd Bergmann , Feng Tang , Petr Mladek , Mauro Carvalho Chehab , Borislav Petkov , YueHaibing , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 7/7] bug: Move WARN_ON() "cut here" into exception handler Message-ID: <20190820205020.1fc22706@oasis.local.home> In-Reply-To: <201908200908.6437DF5@keescook> References: <20190819234111.9019-1-keescook@chromium.org> <20190819234111.9019-8-keescook@chromium.org> <20190820100638.GK2332@hirez.programming.kicks-ass.net> <06ba33fd-27cc-3816-1cdf-70616b1782dd@c-s.fr> <201908200908.6437DF5@keescook> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 20 Aug 2019 09:33:24 -0700 Kees Cook wrote: > > > > diff --git a/lib/bug.c b/lib/bug.c > > > > index 1077366f496b..6c22e8a6f9de 100644 > > > > --- a/lib/bug.c > > > > +++ b/lib/bug.c > > > > @@ -181,6 +181,15 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) > > > > } > > > > } > > > > + /* > > > > + * BUG() and WARN_ON() families don't print a custom debug message > > > > + * before triggering the exception handler, so we must add the > > > > + * "cut here" line now. WARN() issues its own "cut here" before the > > > > + * extra debugging message it writes before triggering the handler. > > > > + */ > > > > + if ((bug->flags & BUGFLAG_PRINTK) == 0) > > > > + printk(KERN_DEFAULT CUT_HERE); > > > > > > I'm not loving that BUGFLAG_PRINTK name, BUGFLAG_CUT_HERE makes more > > > sense to me. > > That's fine -- easy rename. :) > > > Actually it would be BUGFLAG_NO_CUT_HERE then, otherwise all arches not > > using the generic macros will have to add the flag to get the "cut here" > > line. > > I am testing for the lack of the flag (so that only the > CONFIG_GENERIC_BUG with __WARN_FLAGS case needs to set it). I was > thinking of the flag to mean "this reporting flow has already issued > cut-here". It sounds like it would be more logical to have it named > BUGFLAG_NO_CUT_HERE to mean "do not issue a cut-here; it has already > happened"? I will update the patch. > BUGFLAG_HAS_CUT_HERE ? As it shows it was already done? -- Steve