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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 39864C3A5A2 for ; Tue, 10 Sep 2019 09:16:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CB3820872 for ; Tue, 10 Sep 2019 09:16:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ix5XIq52" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729044AbfIJJQZ (ORCPT ); Tue, 10 Sep 2019 05:16:25 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:34529 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726836AbfIJJQY (ORCPT ); Tue, 10 Sep 2019 05:16:24 -0400 Received: by mail-pf1-f196.google.com with SMTP id r12so11207653pfh.1; Tue, 10 Sep 2019 02:16:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=wfhBlXbTlTMX4E76VadOfA+hOSSFiVKlUr5WhybwN6Y=; b=Ix5XIq52ojuczz2WFlndYuPyvegA1xBDLqKlQinxNi/ddwwT7aSp4BE52bdpTtvBZU VGccYwG2QB+jUEvkPdfe009RtiB9HEycmrhIrWHM2Wz5mmZhS9Z/AETPcWfTFmwV3RVr LmnHyXpoIlqloJ3oDoCuKVs3wIKH02w1f1IqNKPq+VKN2iVFQ8lY97MeHbb7nlrdDQjZ a1vYuEugpJMWHAut3i/uQueEv43jrugOrhortyg2TB6eWDbzer1PjupJpjCNdPR/GRIV TFhVK+cu/PfSgVeGkWYqYzXVF/xBJikC6YUBWbu1BJHOGROPTjsqrh8eNAkwfDzk1T8t KXbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=wfhBlXbTlTMX4E76VadOfA+hOSSFiVKlUr5WhybwN6Y=; b=qVutd7aMe3kzHOynRAvUyp4RXnsCk2k13NO3v7MXVegLU8M6bx0N3nR9VoHjhYUK9e AOGSi3eLE2vAzf63NM+x/sbZOW3eAlgdN7kog1wlih/hUh4UE2y1g84jyym+Ijfvw1wQ fGyYk4Mw6Einaj4JDuSVT1WR/6puoUWSaMktOqSY8kMl+/Oj5UJBP6Q2xGDCrI57rfSL u432VeCwExz8H/6mz13zoAm85xn7oOcsT+xDAohmFkd/BpbqUUG3TsM4FH6oXCNzG9u2 E09j/PBgRRl78/selUIcSG9j64Q2p4RvcDCdRhE9KzkHcYben3gP6Pe6VAKuThCNX9V7 SN6g== X-Gm-Message-State: APjAAAWK5rtNKzRmOxqg2YZskMw+NokgPEd65l+V1hmNMgU0bGrfVhQ/ z5ylOapIXRh/4Ux6+PExiMzf3DwF X-Google-Smtp-Source: APXvYqzHxaQmBpWgS74sUCr55Qt//D6scXpE7mF2noH5yrUuPhN0dejzlnIbbX8R57D9IIvydGR9/g== X-Received: by 2002:a65:5cca:: with SMTP id b10mr27422854pgt.365.1568106983856; Tue, 10 Sep 2019 02:16:23 -0700 (PDT) Received: from localhost ([39.7.19.227]) by smtp.gmail.com with ESMTPSA id l26sm20389698pgb.90.2019.09.10.02.16.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 02:16:23 -0700 (PDT) Date: Tue, 10 Sep 2019 18:16:19 +0900 From: Sergey Senozhatsky To: Kees Cook Cc: Sergey Senozhatsky , Andrew Morton , Christophe Leroy , Peter Zijlstra , Drew Davenport , Arnd Bergmann , "Steven Rostedt (VMware)" , Feng Tang , Petr Mladek , Mauro Carvalho Chehab , Borislav Petkov , YueHaibing , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 7/7] bug: Move WARN_ON() "cut here" into exception handler Message-ID: <20190910091619.GA207290@jagdpanzerIV> References: <201908200943.601DD59DCE@keescook> <20190909160539.GA989@tigerII.localdomain> <201909100157.CEE99802C@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201909100157.CEE99802C@keescook> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (09/10/19 01:59), Kees Cook wrote: > On Tue, Sep 10, 2019 at 01:05:39AM +0900, Sergey Senozhatsky wrote: > > On (08/20/19 09:47), Kees Cook wrote: > > [..] > > > + /* > > > + * 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_NO_CUT_HERE) == 0) > > > + printk(KERN_DEFAULT CUT_HERE); > > > > Shouldn't this be pr_warn() or pr_crit()? > > The pr_* helpers here would (potentially) add unwanted prefixes, so > those aren't used. KERN_DEFAULT is used here because that's how it's > always been printed. I didn't want to change that for this refactoring > work. I'm not opposed to it, generally speaking, though. :) I just glanced through CUT_HERE users warn_slowpath_fmt() pr_warn(CUT_HERE) __warn_printk() pr_warn(CUT_HERE) rdma_restrack_clean() pr_err("restrack: %s", CUT_HERE) rdma_restrack_clean() pr_err("restrack: %s", CUT_HERE) + oops/panic end markers are of pr_warn() or pr_crit() log levels. So I thought that maybe we can make it more or less similar. But if it has always been this way (KERN_DEFAULT) then OK. -ss