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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 068B9C10F12 for ; Wed, 17 Apr 2019 09:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1B912173C for ; Wed, 17 Apr 2019 09:46:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MBclKO3Q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731560AbfDQJqT (ORCPT ); Wed, 17 Apr 2019 05:46:19 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:33627 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727013AbfDQJqT (ORCPT ); Wed, 17 Apr 2019 05:46:19 -0400 Received: by mail-pl1-f194.google.com with SMTP id t16so11791164plo.0 for ; Wed, 17 Apr 2019 02:46:18 -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=ZyKJZ47f4xCb2UIIdx1GAFfeyl24qLjgluCWgbDS0Fk=; b=MBclKO3Q2+DkSAKDuAcoiW2DEBEJM7ysNu3Ra6OkomCLFkXfzIB3fe6/j25k7U6prF pA1ri/r05RM0Q5Oy8QgU5OZ0FOIA9Fh0MgIODWwrtOQxN0oGSi+xd48y4dPxBtv/Y9Xh gqACKuwx98xOovJ1LFxXP/pDZm9UYkBFadgD5mH4vZQecB/DLOtmaEktpiKp/jqdrbcn wcJ9QyaUi/krUF1Wz29ZTqhmI7q+ZUSRdpBlrtmuqXCRfA2F4/ijG/dAcb6dlxQEVq3S spV/dkjcQEEbuDAW7/+2CjMqpHlk4Ap38HZaYKZ0f1e27gU6BIfy4wdple+9cG39UOWk viCg== 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=ZyKJZ47f4xCb2UIIdx1GAFfeyl24qLjgluCWgbDS0Fk=; b=c9IjprRa5WEYO2amYrGFqFZQ/wZtnKKYKfMQSnJ7M0n5ufvXUsf5HrXrDR+U/NTB0+ SpAxpiG07J/LK9GeRY+/HdnkoEduhelHQbTSGirnKkRFcAnFg3ztK2wJg9GRnCbu8CNq 2DmY3+S64q2R9w1SGY85lHbarxXdWrmsKKcon19KHWvojgmKXinwkKftEpNdsfQOK1gJ 0cDvOURJdHy0IC4uPKLAexENWI1gRWsR3khaKge3kRgL67oTgo693VdQVO4u8nvNI9Rn lSDxb7F4w2wPnObsPeV2L63ASeYNbHwUxXs9fo7ABe3bdjL5WToyNdvjDx0vsXgDmg8I dBjA== X-Gm-Message-State: APjAAAVQai/3F1MfWJ2R0Kb+BvujUcuXLkoynusSPEeM4XJ6iwKWk6nq maPnqqrw1eeINnLQyNQjAGc= X-Google-Smtp-Source: APXvYqw6l4Pwqg8YjrC6g4FFyAMA8e2V19cPhV31MSi2GmXss/oRmYzAu1hQc8LplC3E3nS+lMuOhA== X-Received: by 2002:a17:902:70c8:: with SMTP id l8mr88795321plt.177.1555494378670; Wed, 17 Apr 2019 02:46:18 -0700 (PDT) Received: from localhost ([110.70.26.221]) by smtp.gmail.com with ESMTPSA id r11sm96502426pga.87.2019.04.17.02.46.16 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 17 Apr 2019 02:46:17 -0700 (PDT) Date: Wed, 17 Apr 2019 18:46:14 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Feng Tang , Andrew Morton , Steven Rostedt , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Kees Cook , Borislav Petkov , ying.huang@intel.com Subject: Re: [PATCH v2] panic: add an option to replay all the printk message in buffer Message-ID: <20190417094614.GB4260@jagdpanzerIV> References: <20190410153718.22905-1-feng.tang@intel.com> <20190416211922.d3c9c6987f0b992da343be52@linux-foundation.org> <20190417064844.ppyqxcx2mgek5455@shbuild888> <20190417091832.z252cvcf4ktxeamv@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190417091832.z252cvcf4ktxeamv@pathway.suse.cz> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (04/17/19 11:18), Petr Mladek wrote: > > My instant thought would be put the console_unlcok() and similar funcs > > under CONFIG_PRINTK protection, while adding nop functions in the "else" > > segment. > > > > But complexer question will be when CONFIG_PRINTK=n, how those console_xxx > > functions should consider these to make compiled binary smaller (though it > > rarely happens). would wait for Petr/Sergey/Steven's insights. > > I guess that it is because console_sem is historically used to > synchronize some unrelated things, espcially in tty code. > Unfortunately, it is not easy to clean this up. > > For this patch, the best solution seems to be using scnprintf() > instead of sprintf(). OK, since we have another chance to re-iterate this. Do we really want to complicate console_unlock() printing loop any further? Asking off chance, can we return back to the idea of adding enum FLUSH_PENDING/FLUSH_ALL to console_flush_on_panic()? Does not look too complex/ugly. --- -void console_flush_on_panic(void) +void console_flush_on_panic(enum console_flush_mode flush_mode) { /* * If someone else is holding the console lock, trylock will fail @@ -2549,6 +2549,10 @@ void console_flush_on_panic(void) */ console_trylock(); console_may_schedule = 0; + if (flush_mode == FLUSH_ALL) { + console_seq = log_first_seq; + console_idx = log_first_idx; + } console_unlock(); } --- -ss