From patchwork Sat Nov 7 02:06:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 321766 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=-9.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 AB19CC5517A for ; Sat, 7 Nov 2020 02:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85BBC22243 for ; Sat, 7 Nov 2020 02:07:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728627AbgKGCHp (ORCPT ); Fri, 6 Nov 2020 21:07:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:49822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728111AbgKGCHa (ORCPT ); Fri, 6 Nov 2020 21:07:30 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 8AA9D208E4; Sat, 7 Nov 2020 02:07:29 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94) (envelope-from ) id 1kbDdY-007lvx-55; Fri, 06 Nov 2020 21:07:28 -0500 Message-ID: <20201107020727.995741226@goodmis.org> User-Agent: quilt/0.66 Date: Fri, 06 Nov 2020 21:06:39 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Daniel Wagner , Tom Zanussi , "Srivatsa S. Bhat" , stable-rt@vger.kernel.org Subject: [PATCH RT 3/6] mm/memcontrol: Disable preemption in __mod_memcg_lruvec_state() References: <20201107020636.598338441@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org 5.4.74-rt42-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior The callers expect disabled preemption/interrupts while invoking __mod_memcg_lruvec_state(). This works mainline because a lock of somekind is acquired. Use preempt_disable_rt() where per-CPU variables are accessed and a stable pointer is expected. This is also done in __mod_zone_page_state() for the same reason. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9bdb75ef6d62..c9d02e2272e1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -752,6 +752,7 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); memcg = pn->memcg; + preempt_disable_rt(); /* Update memcg */ __mod_memcg_state(memcg, idx, val); @@ -767,6 +768,7 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, x = 0; } __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x); + preempt_enable_rt(); } void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)