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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7A29DC5B57D for ; Tue, 2 Jul 2019 08:07:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52DB521479 for ; Tue, 2 Jul 2019 08:07:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054832; bh=vxlSxloGy9FiBx6D4K/fVsTHST9rZqG0BZe4InvsPp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aUqO2Wu7QQiufRdDN5HfJzdB5ounXzec0HzgA5X803YEmragCFo7f3gkLHVAiEWo4 mU8VeM8Xo1fGHfjsJDIEIxta8vwf1suJNoXqVUdTQQOPEvoqWoN9xDG0QdPVdNMTu5 8snY6enXPTKJx8NJkai2Yi7MT3XcQjkVpoYkb8tA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728215AbfGBIHK (ORCPT ); Tue, 2 Jul 2019 04:07:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:54204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728195AbfGBIHH (ORCPT ); Tue, 2 Jul 2019 04:07:07 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 054082184E; Tue, 2 Jul 2019 08:07:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054826; bh=vxlSxloGy9FiBx6D4K/fVsTHST9rZqG0BZe4InvsPp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S+moHf9QWVNBp2ZtqwJt8oVrj1dbrWa/AxhoscTw++Tkx7DPk2ThQHU6BMXwe2lCU r+YRJN4gOp8RX3Ze76mDFxcqyOKojLs8R3AAEAvVw8GNnKxX2bqSAzSUdRmHyp+rpf U6GxdRN6X5166f5qmDUya2cXYDIoRBKTa/WXD6ow= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Geert Uytterhoeven , Thomas Gleixner , Josh Poimboeuf , Peter Zijlstra , Jiri Kosina , Ben Hutchings Subject: [PATCH 4.19 46/72] cpu/speculation: Warn on unsupported mitigations= parameter Date: Tue, 2 Jul 2019 10:01:47 +0200 Message-Id: <20190702080126.998230881@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.564652899@linuxfoundation.org> References: <20190702080124.564652899@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190516070935.22546-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman --- kernel/cpu.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2289,6 +2289,9 @@ static int __init mitigations_parse_cmdl cpu_mitigations = CPU_MITIGATIONS_AUTO; else if (!strcmp(arg, "auto,nosmt")) cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; + else + pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", + arg); return 0; }