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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 530E7C4360C for ; Wed, 2 Oct 2019 19:09:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FC80222BE for ; Wed, 2 Oct 2019 19:09:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729581AbfJBTJL (ORCPT ); Wed, 2 Oct 2019 15:09:11 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36114 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729383AbfJBTIW (ORCPT ); Wed, 2 Oct 2019 15:08:22 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iFjyu-000366-ES; Wed, 02 Oct 2019 20:08:12 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iFjyq-0003gC-6b; Wed, 02 Oct 2019 20:08:08 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Thomas Gleixner" , "Josh Poimboeuf" , "Jiri Kosina" , "Peter Zijlstra" , "Geert Uytterhoeven" , "Greg Kroah-Hartman" Date: Wed, 02 Oct 2019 20:06:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 79/87] cpu/speculation: Warn on unsupported mitigations= parameter In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Geert Uytterhoeven commit 1bf72720281770162c87990697eae1ba2f1d917a upstream. Currently, if the user specifies an unsupported mitigation strategy on the kernel command line, it will be ignored silently. The code will fall back to the default strategy, possibly leaving the system more vulnerable than expected. This may happen due to e.g. a simple typo, or, for a stable kernel release, because not all mitigation strategies have been backported. Inform the user by printing a message. Fixes: 98af8452945c5565 ("cpu/speculation: Add 'mitigations=' cmdline option") Signed-off-by: Geert Uytterhoeven Signed-off-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Peter Zijlstra Cc: Jiri Kosina Cc: Greg Kroah-Hartman Cc: Ben Hutchings Link: https://lkml.kernel.org/r/20190516070935.22546-1-geert@linux-m68k.org [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- kernel/cpu.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -804,6 +804,9 @@ static int __init mitigations_parse_cmdl cpu_mitigations = CPU_MITIGATIONS_OFF; else if (!strcmp(arg, "auto")) cpu_mitigations = CPU_MITIGATIONS_AUTO; + else + pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", + arg); return 0; }