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=-6.8 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,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 AEBB6C606BD for ; Mon, 8 Jul 2019 15:20:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C1BC216C4 for ; Mon, 8 Jul 2019 15:20:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599245; bh=lwJoXo0OMx4jnxVx+rb2Tvlq8NdHDDEO3bUGUSaZ9Ho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MwceHwmjP5f0Xr0HHmWjDzNQmPDn+1cR1zn6J//AruJ5FXwnIsbb46YSyLgMaHR35 ZFSrzHpqMxgjYB3N5eQnBntn5e2JZtC3NFqp3hIZDKMY+cwpUpSdpp5GffRKWlHdcK euvDoDnE9bjZaJky59n5vRuOYaR27s+fE54J370g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387629AbfGHPUo (ORCPT ); Mon, 8 Jul 2019 11:20:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:45804 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387599AbfGHPUm (ORCPT ); Mon, 8 Jul 2019 11:20:42 -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 002BD216FD; Mon, 8 Jul 2019 15:20:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599241; bh=lwJoXo0OMx4jnxVx+rb2Tvlq8NdHDDEO3bUGUSaZ9Ho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jGU226NGFsvhUK/8TEaxejUeGcKu9VJWZYFPioGYkDP1etrFbuigxydyXExkQ2TUW 4E7aMtF6D4hPHya2eTP4tQciUiGu/Sv/qzDgWN+DWWq33LleQCHgctRbTxA6TewNdC Nhk8dPH7oZOC1Lb/fZxwwqgS2A/nPDjlbr0MnqyU= 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 4.9 051/102] cpu/speculation: Warn on unsupported mitigations= parameter Date: Mon, 8 Jul 2019 17:12:44 +0200 Message-Id: <20190708150529.080168444@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190708150525.973820964@linuxfoundation.org> References: <20190708150525.973820964@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 @@ -2245,6 +2245,9 @@ 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; }