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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 E7D8BC43381 for ; Mon, 1 Apr 2019 17:36:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B551E2070B for ; Mon, 1 Apr 2019 17:36:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140197; bh=yPOHKrejMgz+8mjke84X6PrU98t2IgQ60OSskPOAu2M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VOvH2RJlLCsdgyk6NZ+FSSNm1ssrzeQszlF+em2EJVcqu+NWgvk0KFQ6HfN3K7lJ5 bcdQ7L1cEh0t97YRb0k6PWXWVPlEPdn1UauLzQXupe2vJd3C7jnDB1x56lC08pYeIS AdyuT5gw8tst6DTzk2Um0eAtW6bLyMf5dHNuiqvM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387886AbfDARgg (ORCPT ); Mon, 1 Apr 2019 13:36:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:48398 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387697AbfDARge (ORCPT ); Mon, 1 Apr 2019 13:36:34 -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 C172720880; Mon, 1 Apr 2019 17:36:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140193; bh=yPOHKrejMgz+8mjke84X6PrU98t2IgQ60OSskPOAu2M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sjY5iECFM2a16ewqeWV9bztLrCCFB9mOt+mRSRHWH4tRCaKlPkZR0hjJWyv+EmrNe 5stn711Y/NEa+OEFGGuKb9juDos4w1S/TTPgbCYenzQ8NBMe2j30Ct4j80zFIyPaQf eibPpO5XqwTCMvPs7X1/MqT6VG2iO+RbuZ1d+nuc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tianyu Lan , Thomas Gleixner , Konrad Wilk , Josh Poimboeuf , Mukesh Ojha , Peter Zijlstra , Jiri Kosina , Rik van Riel , Andy Lutomirski , Micheal Kelley , "K. Y. Srinivasan" , Linus Torvalds , Borislav Petkov Subject: [PATCH 4.4 125/131] x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y Date: Mon, 1 Apr 2019 19:03:15 +0200 Message-Id: <20190401170101.903598619@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit bebd024e4815b1a170fcd21ead9c2222b23ce9e6 upstream. 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 Acked-by: Greg Kroah-Hartman 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: Linus Torvalds Cc: Borislav Petkov Cc: K. Y. Srinivasan Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190326163811.598166056@linutronix.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/Kconfig | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1970,14 +1970,8 @@ config PHYSICAL_ALIGN Don't change this unless you know what you are doing. config HOTPLUG_CPU - bool "Support for hot-pluggable CPUs" + def_bool y depends on SMP - ---help--- - Say Y here to allow turning CPUs off and on. CPUs can be - controlled through /sys/devices/system/cpu. - ( Note: power management support will enable this option - automatically on SMP systems. ) - Say N if you want to disable CPU hotplug. config BOOTPARAM_HOTPLUG_CPU0 bool "Set default setting of cpu0_hotpluggable"