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=unavailable 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 99C37C06510 for ; Tue, 2 Jul 2019 08:16:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A6D9205ED for ; Tue, 2 Jul 2019 08:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562055408; bh=c43FvKQyIGggJWe3cFvt6aywY7QSwZwhDAgmHHoL9gM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uAUbUjdsBf4x0JoigsIS6iRVR6QP+apxKf+Mchv8OoGl6QyQHB9BL+0Sz9h2KTMEZ Y8umGjjUGJlGylUubvzYLdIjBYNFEKhdnQ6dFnaji8B6/FhpCkQPenZwo6xCUZxVOU mbXIruzC2Py0eh/s3NemCcsREV55eq2jwlqLgGlU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727451AbfGBIDa (ORCPT ); Tue, 2 Jul 2019 04:03:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:48450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727434AbfGBID1 (ORCPT ); Tue, 2 Jul 2019 04:03:27 -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 4DF2321479; Tue, 2 Jul 2019 08:03:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054606; bh=c43FvKQyIGggJWe3cFvt6aywY7QSwZwhDAgmHHoL9gM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I3kFQ6YW2UK8ffvRLSVQrJZc+ZPqceCtVy3nJDqRfWwJ8jt/OfSspdxofDw+Vvy3A DVbOqrsDCz/0zjZHSO0KziXm+bZMJzTLU9uSV0Nrn1lmDoqukErgNbmnE2lRTXvg+w zkEpahrU9jUk/nZhfHIXFvoKmF+bU7CfjTFnjAwg= 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 5.1 27/55] cpu/speculation: Warn on unsupported mitigations= parameter Date: Tue, 2 Jul 2019 10:01:35 +0200 Message-Id: <20190702080125.502302944@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.103022729@linuxfoundation.org> References: <20190702080124.103022729@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 @@ -2315,6 +2315,9 @@ 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; }