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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0734FC6FA99 for ; Fri, 10 Mar 2023 14:44:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232986AbjCJOol (ORCPT ); Fri, 10 Mar 2023 09:44:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232974AbjCJOoN (ORCPT ); Fri, 10 Mar 2023 09:44:13 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5854C106A2A for ; Fri, 10 Mar 2023 06:44:12 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1730BB8228E for ; Fri, 10 Mar 2023 14:44:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 689C3C4339E; Fri, 10 Mar 2023 14:44:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678459449; bh=51J+DjP2V28KQkpv+0RnHKAwsuKzvMf0gOMfTNDOJzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xlmot18N8czmUbsViD1jQPVxJAHRTQu5t2Ps7fYhAEUb+2WyzoMPpZE/vN4w9m+EX SW39L79VmRGjGCmRswhgyUTNesrq5uOVjBtX/5YkAQAxcFgkF9+JUUNC++gnIUeB8o Cp7NnQlOb+7TozC6sp/K1uyL2YQvX5ZyFOGcb15o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Valentin Schneider , Reinette Chatre , Borislav Petkov Subject: [PATCH 5.4 350/357] x86/resctrl: Apply READ_ONCE/WRITE_ONCE to task_struct.{rmid,closid} Date: Fri, 10 Mar 2023 14:40:39 +0100 Message-Id: <20230310133750.112162762@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310133733.973883071@linuxfoundation.org> References: <20230310133733.973883071@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Valentin Schneider commit 6d3b47ddffed70006cf4ba360eef61e9ce097d8f upstream. A CPU's current task can have its {closid, rmid} fields read locally while they are being concurrently written to from another CPU. This can happen anytime __resctrl_sched_in() races with either __rdtgroup_move_task() or rdt_move_group_tasks(). Prevent load / store tearing for those accesses by giving them the READ_ONCE() / WRITE_ONCE() treatment. Signed-off-by: Valentin Schneider Signed-off-by: Reinette Chatre Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/9921fda88ad81afb9885b517fbe864a2bc7c35a9.1608243147.git.reinette.chatre@intel.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/resctrl_sched.h | 11 +++++++---- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 +++++----- 2 files changed, 12 insertions(+), 9 deletions(-) --- a/arch/x86/include/asm/resctrl_sched.h +++ b/arch/x86/include/asm/resctrl_sched.h @@ -56,19 +56,22 @@ static void __resctrl_sched_in(void) struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state); u32 closid = state->default_closid; u32 rmid = state->default_rmid; + u32 tmp; /* * If this task has a closid/rmid assigned, use it. * Else use the closid/rmid assigned to this cpu. */ if (static_branch_likely(&rdt_alloc_enable_key)) { - if (current->closid) - closid = current->closid; + tmp = READ_ONCE(current->closid); + if (tmp) + closid = tmp; } if (static_branch_likely(&rdt_mon_enable_key)) { - if (current->rmid) - rmid = current->rmid; + tmp = READ_ONCE(current->rmid); + if (tmp) + rmid = tmp; } if (closid != state->cur_closid || rmid != state->cur_rmid) { --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -563,11 +563,11 @@ static int __rdtgroup_move_task(struct t */ if (rdtgrp->type == RDTCTRL_GROUP) { - tsk->closid = rdtgrp->closid; - tsk->rmid = rdtgrp->mon.rmid; + WRITE_ONCE(tsk->closid, rdtgrp->closid); + WRITE_ONCE(tsk->rmid, rdtgrp->mon.rmid); } else if (rdtgrp->type == RDTMON_GROUP) { if (rdtgrp->mon.parent->closid == tsk->closid) { - tsk->rmid = rdtgrp->mon.rmid; + WRITE_ONCE(tsk->rmid, rdtgrp->mon.rmid); } else { rdt_last_cmd_puts("Can't move task to different control group\n"); return -EINVAL; @@ -2177,8 +2177,8 @@ static void rdt_move_group_tasks(struct for_each_process_thread(p, t) { if (!from || is_closid_match(t, from) || is_rmid_match(t, from)) { - t->closid = to->closid; - t->rmid = to->mon.rmid; + WRITE_ONCE(t->closid, to->closid); + WRITE_ONCE(t->rmid, to->mon.rmid); /* * Order the closid/rmid stores above before the loads