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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 2AAB2C433DF for ; Fri, 10 Jul 2020 11:28:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0629820772 for ; Fri, 10 Jul 2020 11:28:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="R+thKef1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727834AbgGJL2T (ORCPT ); Fri, 10 Jul 2020 07:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44032 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726820AbgGJL2K (ORCPT ); Fri, 10 Jul 2020 07:28:10 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57CE6C08C5CE; Fri, 10 Jul 2020 04:28:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3D7HcbVvasTwDLZD4YAaihs84eO23KPCl16ZChSDu2M=; b=R+thKef1a76pE65/41vHX+3lv3 8rKgvdJkIb+n1O571lv2KUon0j/BUoUWCdRGZPxW7CeOtjVXoqp0bnXVreGM6reSeE3fLmkaILdkX g/X09WiEsiacoldznMOBN8qu7deTd7tWYPGj0PBsD2TjtLae5TOBfR+WG2WVLfShipAU2zfEeRkku 9OREHHOza/y6f/p/Wy/AYo5sVBRXv7FS86PNDt/l7g3U3wbWLM/CZdtQTGMCvezJVZ2onIQ7H2AfD 8QOthqDQ3vmQbXubYLzXvB1L79kj6oZ3mYAsLg8sekkCCzA8PwvZOFvU4t0tc9MRyfmh3yOgvg3G7 V3oHT3nw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtrCF-0006JB-S9; Fri, 10 Jul 2020 11:28:04 +0000 Date: Fri, 10 Jul 2020 12:28:03 +0100 From: Matthew Wilcox To: Randy Dunlap Cc: Changming Liu , keescook@chromium.org, mcgrof@kernel.org, yzaikin@google.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] sysctl: add bound to panic_timeout to prevent overflow Message-ID: <20200710112803.GI12769@casper.infradead.org> References: <1594351343-11811-1-git-send-email-charley.ashbringer@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jul 09, 2020 at 08:31:39PM -0700, Randy Dunlap wrote: > > +/* this is needed for setting boundery for panic_timeout to prevent it from overflow*/ > > boundary (or max value) overflow */ > > > +static int panic_time_max = INT_MAX / 1000; Or just simplify the comment. /* Prevent overflow in panic() */ Or perhaps better, fix panic() to not overflow. - for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { + for (i = 0; i / 1000 < panic_timeout; i += PANIC_TIMER_STEP) { you probably also want to change i to be a long long or the loop may never terminate.