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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 E2D51C433DB for ; Mon, 11 Jan 2021 10:51:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ABDE9224D3 for ; Mon, 11 Jan 2021 10:51:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729525AbhAKKu7 (ORCPT ); Mon, 11 Jan 2021 05:50:59 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:37944 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729276AbhAKKux (ORCPT ); Mon, 11 Jan 2021 05:50:53 -0500 Date: Mon, 11 Jan 2021 10:50:08 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1610362209; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=G/n3hDKcZpF5HD2TgAvXu3ZbdawIkPcUNQtQvBVSYuw=; b=CwZJVTwpAk0cElyqTTROCVBsK7dJuC8/+hsYRlLdFeMaQRRV7i19CO4/b0aCe+OvP2/5n3 3AhDL/StcsVcDbMrlzcbFDKLjbmU0uMUC0OFhzaKY9v/7b0Ej/HQAvJIrY/1oQLntw/u4B R3DSrkWujEwx2n54T1k6ESCdOe4fp3QS1e+3P3iRjtLdovWi6x35n4TtlrxRD7FBPNyUEQ PEf8yFVduBgp0mqNXqHzOvCfMgRGt7MNkTiE6z1Ow/1DJqtFweA9ff5WexQeJX4Mje52BZ fdoERISKi24kxwrXMQU13DXiM3UedDS9syVLL9vVNrkvAsEHC6McRSdbHLLZdg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1610362209; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=G/n3hDKcZpF5HD2TgAvXu3ZbdawIkPcUNQtQvBVSYuw=; b=AnSY9fliONn/qBoiExOtRiH9yi4IVMw1fl4bN4+C0XGTkeMQJaQ8HAhuUiKtp/+yLhZj3p 3g1WDe9yr3S8IQCw== From: "tip-bot2 for Valentin Schneider" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/cache] x86/resctrl: Apply READ_ONCE/WRITE_ONCE to task_struct.{rmid,closid} Cc: Valentin Schneider , Reinette Chatre , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: =?utf-8?q?=3C9921fda88ad81afb9885b517fbe864a2bc7c35a9=2E16082?= =?utf-8?q?43147=2Egit=2Ereinette=2Echatre=40intel=2Ecom=3E?= References: =?utf-8?q?=3C9921fda88ad81afb9885b517fbe864a2bc7c35a9=2E160824?= =?utf-8?q?3147=2Egit=2Ereinette=2Echatre=40intel=2Ecom=3E?= MIME-Version: 1.0 Message-ID: <161036220889.414.7823554165094952734.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/cache branch of tip: Commit-ID: 6d3b47ddffed70006cf4ba360eef61e9ce097d8f Gitweb: https://git.kernel.org/tip/6d3b47ddffed70006cf4ba360eef61e9ce097d8f Author: Valentin Schneider AuthorDate: Thu, 17 Dec 2020 14:31:21 -08:00 Committer: Borislav Petkov CommitterDate: Mon, 11 Jan 2021 11:43:23 +01:00 x86/resctrl: Apply READ_ONCE/WRITE_ONCE to task_struct.{rmid,closid} 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 --- arch/x86/include/asm/resctrl.h | 11 +++++++---- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 +++++----- 2 files changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h index 0760306..d60ed06 100644 --- a/arch/x86/include/asm/resctrl.h +++ b/arch/x86/include/asm/resctrl.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) { diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 37f37df..f9190ad 100644 --- 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 task_struct *tsk, */ 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; @@ -2310,8 +2310,8 @@ static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *to, 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); /* * If the task is on a CPU, set the CPU in the mask.