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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 2012AC65C20 for ; Mon, 8 Oct 2018 16:30:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E459A2089D for ; Mon, 8 Oct 2018 16:30:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E459A2089D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=windriver.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 S1727226AbeJHXm6 (ORCPT ); Mon, 8 Oct 2018 19:42:58 -0400 Received: from mail1.windriver.com ([147.11.146.13]:41964 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726731AbeJHXm5 (ORCPT ); Mon, 8 Oct 2018 19:42:57 -0400 Received: from ALA-HCA.corp.ad.wrs.com ([147.11.189.40]) by mail1.windriver.com (8.15.2/8.15.1) with ESMTPS id w98GUFoV019858 (version=TLSv1 cipher=AES128-SHA bits=128 verify=FAIL); Mon, 8 Oct 2018 09:30:15 -0700 (PDT) Received: from [128.224.162.216] (128.224.162.216) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 8 Oct 2018 09:30:15 -0700 Subject: Re: [PATCH v5 4/4] printk: Give error on attempt to set log buffer length to over 4G To: Petr Mladek CC: , , References: <1538239553-81805-1-git-send-email-zhe.he@windriver.com> <1538239553-81805-4-git-send-email-zhe.he@windriver.com> <20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz> From: He Zhe Message-ID: <2a9ea0e6-f1df-7dcd-e2e8-383e297ccc5f@windriver.com> Date: Tue, 9 Oct 2018 00:30:12 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [128.224.162.216] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年10月08日 21:59, Petr Mladek wrote: > I tried this patch with log_buf_len=5G. The kernel did not crash > but dmesg shown some mess. There are several 32-bit variables > to store the size, for example: > > static u32 log_buf_len = __LOG_BUF_LEN; > u32 log_buf_len_get(void) > static u32 log_first_idx; > static u32 log_next_idx; > > I guess that the code somewhere does not detect an overflows > correctly. > > I am not motivated enought to add support for such huge message > buffer. Therefore I suggest to limit it to 32G for now. I'm also fine with this suggestion. Thanks. Zhe