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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 F1CFCC83003 for ; Tue, 28 Apr 2020 02:59:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B5C3D206B8 for ; Tue, 28 Apr 2020 02:59:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Ol0vYtFr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5C3D206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sqoOfS7MNi6ELxlCWalBd3hb3ki9AV6PsKN8bYRPFW8=; b=Ol0vYtFrs52YNc WL+0t5SDJcxjB4rYUN8SAkxhc+EcYLA6tniaKvo4PrhIKBI0ZYSVc5ZXpGasOpIUs10iFqeds/e22 9nzh64cnEyKE3Q3Cdauq2LVODOgvudB25CQIMnw5z7RZIAiv8RinmlII/bZMir/3efOwKx6uKbJ2E DbRXKFUeBg30zzDnhxJ5MHS3jMdyPcLwMHCc8myOTzlmn7z1QPII7n63nfoN95QpXUvGjlV5oRXSu xadA1u+q9nqzwd+mf9kJSiC0DG8knbNMVTEGjmjpY0kg5YbAIDh6oFxNAeX1orYUuaqtpui92A07G mjXcddilTJGxr5SUg/OQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jTGTN-000579-Sz; Tue, 28 Apr 2020 02:59:49 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jTGTL-00056F-8U for linux-arm-kernel@lists.infradead.org; Tue, 28 Apr 2020 02:59:48 +0000 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3FE0E206B8; Tue, 28 Apr 2020 02:59:46 +0000 (UTC) Date: Mon, 27 Apr 2020 22:59:44 -0400 From: Steven Rostedt To: Gavin Shan Subject: Re: [PATCH] arm64/mm: Reject invalid NUMA option Message-ID: <20200427225944.185d4431@gandalf.local.home> In-Reply-To: <20200427225406.7cacc796@gandalf.local.home> References: <20200424045314.16017-1-gshan@redhat.com> <20200424101132.GC1167@C02TD0UTHF1T.local> <20200427225406.7cacc796@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200427_195947_317370_3888370B X-CRM114-Status: GOOD ( 16.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , catalin.marinas@arm.com, linux-kernel@vger.kernel.org, shan.gavin@gmail.com, will@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 27 Apr 2020 22:54:06 -0400 Steven Rostedt wrote: > On Tue, 28 Apr 2020 10:59:14 +1000 > Gavin Shan wrote: > > > Hi Mark, > > > > On 4/24/20 8:11 PM, Mark Rutland wrote: > > > [Adding Steve, who added str_has_prefix()] > > > > > > On Fri, Apr 24, 2020 at 02:53:14PM +1000, Gavin Shan wrote: > > >> The NUMA option is parsed by str_has_prefix() and the invalid option > > >> like "numa=o" can be regarded as "numa=off" wrongly. > > > > > > Are you certain that can pass? If that can happen, str_has_prefix() is > > > misnamed and does not seem to do what its kerneldoc says it does, as > > > "off" is not a prefix of "o". > > > > > > > Yes, It's possible. str_has_prefix() depends on strncmp(). In this particular > > case, it's equal to the snippet of code as below: strncmp() returns zero. > > str_has_prefix() returns 3. > > Wait! strncmp("o", "off", 3) returns zero? > > That to me looks like a bug! > > This means str_has_prefix() is broken in other areas as well. > > > > > > int strncmp(const char *cs, const char *ct, size_t count) > > { > > unsigned char c1, c2; > > > > while (count) { > > c1 = *cs++; > > c2 = *ct++; > > if (c1 != c2) > > return c1 < c2 ? -1 : 1; > > if (!c1) /* break after first character is compared */ > > Crap! That is totally wrong! Looking at this again, it's not wrong. But how did we get here if c2 isn't zero as well? -- Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel