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 D44D2C04ABB for ; Thu, 13 Sep 2018 14:28:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 804722147C for ; Thu, 13 Sep 2018 14:28:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uJWV5OFV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 804722147C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727972AbeIMThz (ORCPT ); Thu, 13 Sep 2018 15:37:55 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:35255 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727841AbeIMThy (ORCPT ); Thu, 13 Sep 2018 15:37:54 -0400 Received: by mail-pg1-f195.google.com with SMTP id 7-v6so2840449pgf.2 for ; Thu, 13 Sep 2018 07:28:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=xvfoXrHPe7ea3dZN/E6pi8vHopvaBJ0KysWUAGYUNtM=; b=uJWV5OFVDroMIkOtv8d/+EYITgcdmWHgFV77yAikqekGNW75IfiMtD6UwjB3eeqWqX ov7EOUbCx8OlBQZ06xmvSooRYv5POGZ0M1V2dIleagQ+nH/HNdjIZ7YtAirXsO7DZxIF znCi8ExkOryGkERPvu7KSLHz2uqMBgxnCoZ3TDfQ277M/4cC04MGzTS+xqMgHBZE8cgs GMbckZVUmAagYWbAXN1qY2zrIVeBe6gJ9RxGOvAaAYmoCjxFfz9B/K1fQ8xfpkjwjP0d lcDcTNKsci6f76sE77l2OL//emyBEd1REfA2aEbSTKNL1Llf47YaxkJQPLCAaj/9uCm1 uYwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=xvfoXrHPe7ea3dZN/E6pi8vHopvaBJ0KysWUAGYUNtM=; b=lTcVCzmX4Y3u1zN1LFRFN1A/+M3uavRNQAfCJg4SDntAHgyngF4QS+OGMCUN/N6lDs SX4iiBTb7Dgxzy90rt7AGkwHgTYswPg8r8rlgVG6yYC6MYSCCn4ZV0W7M8Db+jcGCdT/ kPrayTRk1VJOYl65iVjiAMd0sJlNjzlNLoRrZw+d9LYK36aHhwrtmAgsD4mmhFYDGngv 2zXPk9ZPbiECWN9FTxz633EUbs72ChmoaKVpnE6bSekjBUcshuYW+fW0yWfDkv4vZwDH Y++ZMbZDPsyC2mWuhSRCyog6YO1/qHCvi5OiuRpEga9Urfw1zzexzExZkZRV4wxir5AA eceg== X-Gm-Message-State: APzg51CVXv7UyjKTrjBdzsc6OIpIf3kIEYvEYfrxHTgaTtcRE5e4tF6J KNAXYvkUI0G9nZ+M1Jh3pjU= X-Google-Smtp-Source: ANB0VdZ2klTZtKz5OuB4jWIsOCq7ztOdANJcCBU/M5DOnpBMgF6BYV1ZRxBjMINOcXIMvRIsKggb+w== X-Received: by 2002:a63:1a1a:: with SMTP id a26-v6mr7422134pga.449.1536848888421; Thu, 13 Sep 2018 07:28:08 -0700 (PDT) Received: from localhost ([121.137.63.184]) by smtp.gmail.com with ESMTPSA id v82-v6sm5743853pfd.64.2018.09.13.07.28.06 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 13 Sep 2018 07:28:06 -0700 (PDT) From: Sergey Senozhatsky X-Google-Original-From: Sergey Senozhatsky Date: Thu, 13 Sep 2018 23:28:02 +0900 To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Alexander Potapenko , Sergey Senozhatsky , Dmitriy Vyukov , penguin-kernel@i-love.sakura.ne.jp, kbuild test robot , syzkaller , LKML , Linus Torvalds , Andrew Morton Subject: Re: [PATCH] printk: inject caller information into the body of message Message-ID: <20180913142802.GB517@tigerII.localdomain> References: <20180620091541.GB444@jagdpanzerIV> <20180620110759.GD444@jagdpanzerIV> <20180620130628.GA1000@tigerII.localdomain> <20180912065307.GA606@jagdpanzerIV> <20180912120548.4280f04a@vmware.local.home> <20180913071204.GA604@jagdpanzerIV> <20180913122625.6ieyexpcmlc5z2it@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180913122625.6ieyexpcmlc5z2it@pathway.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (09/13/18 14:26), Petr Mladek wrote: > > + > > +int vpr_line(struct pr_line *pl, const char *fmt, va_list args) > > +{ > > + struct seq_buf *s = &pl->sb; > > + int ret, len; > > + > > + if (fmt[0] == '\n') { > > + pr_line_flush(pl); > > + return 0; > > + } > > You would need to check if fmt[1] == '\0'. But then you would need > to be careful about a possible buffer overflow. I would personally > avoid this optimization. Good call. It was a fast path for pr_cont("\n"). But it made me wondering and I did some grepping arch/m68k/kernel/traps.c: pr_cont("\n "); arch/m68k/kernel/traps.c: pr_cont("\n "); kernel/trace/ftrace.c: pr_cont("\n expected tramp: %lx\n", ip); Lovely. It will take us some time. > > + ret = seq_buf_vprintf(s, fmt, args); > > + > > + len = seq_buf_used(s); > > + if (len && s->buffer[len - 1] == '\n') > > + pr_line_flush(pl); > > This would cause that pr_line_flush() won't be strictly needed. > Also it would encourage people to use this feature a more > complicated way (for more lines). Do we really want this? Not that I see any problems with pr_line_flush(). But can drop it, sure. pr_line() is a replacement for pr_cont() and as such it's not for multi-line buffering. -ss