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=-5.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 CE31CC43381 for ; Wed, 27 Mar 2019 01:12:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DFCA213A2 for ; Wed, 27 Mar 2019 01:12:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553649178; bh=tbmc6N+Ba9QLx5qC/HdtUY3NQBGbPdk01TGWATRrEOE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=v5cVYzBRBSiJVSm0O4s7Ks6Y3tx8qmpObscy6+kt7c1OuJqMAy2eLYLG9SgduJQQn HGoOkRfqO8uzR3Htck+rwWKfR8ad6i+qUQy8O8w1O12AHsURjkWcU8kbVNQEeB7o4Q 1KbPz58v9f7E0af8cVnkJcyQFmkeQBFzX4cyCQAY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732421AbfC0BM5 (ORCPT ); Tue, 26 Mar 2019 21:12:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:57572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726377AbfC0BM4 (ORCPT ); Tue, 26 Mar 2019 21:12:56 -0400 Received: from localhost (mobile-166-137-177-030.mycingular.net [166.137.177.30]) (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 727B5208E4; Wed, 27 Mar 2019 01:12:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553649176; bh=tbmc6N+Ba9QLx5qC/HdtUY3NQBGbPdk01TGWATRrEOE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pNu5ppDiwteIUYheXnJW+opTzRyyFwrxvKAnlVjO3ZNwHwZLdwAdEWs4j7WhUapow oV5SBqiGjjQuvOFGSHaR2roFKyhqi1FwluHmLpqKTmRuHe+EsFvKifGuN8F2LaqVRm dx/ZkRM5LpWFAi/xYAtBX8toht3M/pU7PJkbKv/Q= Date: Wed, 27 Mar 2019 10:12:51 +0900 From: Greg KH To: Thomas Gleixner Cc: LKML , Tianyu Lan , Konrad Wilk , Josh Poimboeuf , Mukesh Ojha , Peter Zijlstra , Jiri Kosina , Rik van Riel , Andy Lutomirski , Micheal Kelley , "K. Y. Srinivasan" , Linus Torvalds , Borislav Petkov , x86@kernel.org Subject: Re: [patch 2/2] x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y Message-ID: <20190327011251.GB3099@kroah.com> References: <20190326163604.348882514@linutronix.de> <20190326163811.598166056@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190326163811.598166056@linutronix.de> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 26, 2019 at 05:36:06PM +0100, Thomas Gleixner wrote: > The SMT disable 'nosmt' command line argument is not working properly when > CONFIG_HOTPLUG_CPU is disabled. The teardown of the sibling CPUs which are > required to be brought up due to the MCE issues, cannot work. The CPUs are > then kept in a half dead state. > > As the 'nosmt' functionality has become popular due to the speculative > hardware vulnerabilities, the half torn down state is not a proper solution > to the problem. > > Enforce CONFIG_HOTPLUG_CPU=y when SMP is enabled so the full operation is > possible. > > Reported-by: Tianyu Lan > Signed-off-by: Thomas Gleixner > Cc: Konrad Wilk > Cc: Josh Poimboeuf > Cc: Mukesh Ojha > Cc: Peter Zijlstra > Cc: Jiri Kosina > Cc: Rik van Riel > Cc: Andy Lutomirski > Cc: Micheal Kelley > Cc: K. Y. Srinivasan > Cc: Greg KH > Cc: Linus Torvalds > Cc: Borislav Petkov > Cc: stable@vger.kernel.org > --- > arch/x86/Kconfig | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) Acked-by: Greg Kroah-Hartman