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=-2.1 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 5D44EC43382 for ; Tue, 25 Sep 2018 12:16:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 064CA2086B for ; Tue, 25 Sep 2018 12:16:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E0Atajst" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 064CA2086B 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 S1728991AbeIYSXc (ORCPT ); Tue, 25 Sep 2018 14:23:32 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:34812 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727441AbeIYSXc (ORCPT ); Tue, 25 Sep 2018 14:23:32 -0400 Received: by mail-wm1-f65.google.com with SMTP id j25-v6so12478396wmc.1 for ; Tue, 25 Sep 2018 05:16:14 -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=rW/kSYu8LTrr+4zLRwegRUrIu36BbxqKZbqWHu6JcrM=; b=E0AtajstKCg7ek8UEOAMGVth6A0GTdaz4E4oGR8vWuEBpncTe3GF8MXJ2ZSkeCGObx 1gwUPoDVZcbfvfLgqTdDZCqB2pfAR+dwrsdwI/ERBzlwUvOmyMcRf2vkFW5LtWicX2or vRRlCpBVik2qxppjndHWnGDaz4e8J2nhyHDA0qN3qQ8nbv2u9/qh0K5YbfPB+7fevygB ty3K8zOHfIBA3cxNCjdC+emOUWhssOBoJ/b05peoHG8NdMhZ6yJIheXXYDDonmF1fnzi VtJOSsP3TZg/W09iJSdE+LxylDzSCv8G8XfixoMpqeCdF3An3IjOzRYbHOaJtLbZ1zHK ljOg== 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=rW/kSYu8LTrr+4zLRwegRUrIu36BbxqKZbqWHu6JcrM=; b=kCTZLgZIeutNJK1P7Rpd53yqPHx40seD9lvTRrGA1X/8v+lncghGIluU1oTveZmEHg fo5f0gAHzaOMkj77mgadV20kWDJ5rvPaYH52gbvLKuy9oRHATZpep0XgMY6P9fCoOAjt T8F5BIntgcXi1iqmanWSeC6QgZCOsOMNmdOswMnDUNAiRoCsK9WjsaGj5kbZ7/UHJitw 0ahuUIw8bpL25geW/YQtsWy5y3Ypi6IdctIA19wFHEeO7tr9SUn+yqKr0B7N1G8r8NiH Tqee5Ph/X1cSRdDAa0jubEOE5HznjP7on+S0ql0Pq+vT17d/kSgixD1kx+5vQ6mzrRMv iDJA== X-Gm-Message-State: ABuFfogN0n1VwpJ2xMAH4F+pQX+Nmpp1sTGVzvNEArr5JM+LAHAQm7KJ teI7DwG7qOncwHY/WmelP6M= X-Google-Smtp-Source: ACcGV62RvyRhqh/tjtQmFymRfgcwir9/vcWSZRQ8o1iBhCM6RsHKG53E6VzhMcdrgR2xxKTwNXUB8A== X-Received: by 2002:a1c:cf8a:: with SMTP id f132-v6mr518383wmg.0.1537877774210; Tue, 25 Sep 2018 05:16:14 -0700 (PDT) Received: from localhost ([178.121.95.75]) by smtp.gmail.com with ESMTPSA id p11-v6sm2837809wrd.74.2018.09.25.05.16.13 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 25 Sep 2018 05:16:13 -0700 (PDT) From: Sergey Senozhatsky X-Google-Original-From: Sergey Senozhatsky Date: Tue, 25 Sep 2018 21:16:04 +0900 To: He Zhe Cc: Petr Mladek , Steven Rostedt , Sergey Senozhatsky , sergey.senozhatsky@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] printk: Fix panic caused by passing log_buf_len to command line Message-ID: <20180925121604.GC523@tigerII.localdomain> References: <1537291068-443145-1-git-send-email-zhe.he@windriver.com> <20180919015030.GA423@jagdpanzerIV> <6c354803-5341-7237-9ee3-7882252c7483@windriver.com> <20180919023932.GA14090@jagdpanzerIV> <20180918224312.6e9aef50@vmware.local.home> <1545bc85-b64a-4b45-d40f-79567ac621dc@windriver.com> <20180920123056.27b2cf18@gandalf.local.home> <20180921073753.mqayzofcofpmhiyu@pathway.suse.cz> <02b53bc1-3803-50b1-d07e-a7962f9e5688@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <02b53bc1-3803-50b1-d07e-a7962f9e5688@windriver.com> 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 (09/22/18 23:36), He Zhe wrote: > I'd like to fix the above issues. But can I have your opinions about how to > handle the syscall? Hmm. This part is complex, I need to look at it more. A signed int is a good buffer size limit for 32-bit user space. But this also means that syslog might experience some problems doing SYSLOG_ACTION_READ_ALL on a 32-bit system with a 4G log_buf. Not to mention SYSLOG_ACTION_READ_ALL on a 64-bit system with a log_buf=32G. So *maybe* things are alredy a bit broken in this department. Dunno, need to think more. -ss