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 B44AEC77B7C for ; Mon, 17 Apr 2023 15:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229627AbjDQPht (ORCPT ); Mon, 17 Apr 2023 11:37:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbjDQPhs (ORCPT ); Mon, 17 Apr 2023 11:37:48 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87FBC12B for ; Mon, 17 Apr 2023 08:37:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681745821; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xRM//pu2PbffDmZmm4sygKu4gI9AZUnAce2CMw7PLTI=; b=JyrGKQW+hka8thY+jUItpB8sQCnB2gzxeYXHNLfuJTBcEyd+gfGF701MMj6t8hR5cC6NXi ghERlokoj7dR2T//RJFqomc/hnsDS05CicKeWHYf1kIZtUCpvVIkBYcfniZ0CQulgO875d Fem5SWw0t4rjbEkK74CmPw331ArF0E4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-647-KMee7r3lOPSIvVdn1EoI_g-1; Mon, 17 Apr 2023 11:36:56 -0400 X-MC-Unique: KMee7r3lOPSIvVdn1EoI_g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1C93885C6E8; Mon, 17 Apr 2023 15:36:56 +0000 (UTC) Received: from llong.com (dhcp-17-153.bos.redhat.com [10.18.17.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id DE8E0C15BA0; Mon, 17 Apr 2023 15:36:55 +0000 (UTC) From: Waiman Long To: Greg Kroah-Hartman , stable@vger.kernel.org Cc: Tejun Heo , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Giuseppe Scrivano , Waiman Long Subject: [PATCH 5.15 2/3] cgroup/cpuset: Make cpuset_fork() handle CLONE_INTO_CGROUP properly Date: Mon, 17 Apr 2023 11:36:46 -0400 Message-Id: <20230417153647.3374211-2-longman@redhat.com> In-Reply-To: <20230417153647.3374211-1-longman@redhat.com> References: <20230417153647.3374211-1-longman@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 42a11bf5c5436e91b040aeb04063be1710bb9f9c upstream. By default, the clone(2) syscall spawn a child process into the same cgroup as its parent. With the use of the CLONE_INTO_CGROUP flag introduced by commit ef2c41cf38a7 ("clone3: allow spawning processes into cgroups"), the child will be spawned into a different cgroup which is somewhat similar to writing the child's tid into "cgroup.threads". The current cpuset_fork() method does not properly handle the CLONE_INTO_CGROUP case where the cpuset of the child may be different from that of its parent. Update the cpuset_fork() method to treat the CLONE_INTO_CGROUP case similar to cpuset_attach(). Since the newly cloned task has not been running yet, its actual memory usage isn't known. So it is not necessary to make change to mm in cpuset_fork(). Fixes: ef2c41cf38a7 ("clone3: allow spawning processes into cgroups") Reported-by: Giuseppe Scrivano Signed-off-by: Waiman Long Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 62 ++++++++++++++++++++++++++++-------------- 1 file changed, 42 insertions(+), 20 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index a7bbe277ae66..3a7690450a3b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2238,16 +2238,33 @@ static void cpuset_cancel_attach(struct cgroup_taskset *tset) } /* - * Protected by cpuset_rwsem. cpus_attach is used only by cpuset_attach() + * Protected by cpuset_rwsem. cpus_attach is used only by cpuset_attach_task() * but we can't allocate it dynamically there. Define it global and * allocate from cpuset_init(). */ static cpumask_var_t cpus_attach; +static nodemask_t cpuset_attach_nodemask_to; + +static void cpuset_attach_task(struct cpuset *cs, struct task_struct *task) +{ + percpu_rwsem_assert_held(&cpuset_rwsem); + + if (cs != &top_cpuset) + guarantee_online_cpus(task, cpus_attach); + else + cpumask_copy(cpus_attach, task_cpu_possible_mask(task)); + /* + * can_attach beforehand should guarantee that this doesn't + * fail. TODO: have a better way to handle failure here + */ + WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); + + cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); + cpuset_update_task_spread_flags(cs, task); +} static void cpuset_attach(struct cgroup_taskset *tset) { - /* static buf protected by cpuset_rwsem */ - static nodemask_t cpuset_attach_nodemask_to; struct task_struct *task; struct task_struct *leader; struct cgroup_subsys_state *css; @@ -2262,20 +2279,8 @@ static void cpuset_attach(struct cgroup_taskset *tset) guarantee_online_mems(cs, &cpuset_attach_nodemask_to); - cgroup_taskset_for_each(task, css, tset) { - if (cs != &top_cpuset) - guarantee_online_cpus(task, cpus_attach); - else - cpumask_copy(cpus_attach, task_cpu_possible_mask(task)); - /* - * can_attach beforehand should guarantee that this doesn't - * fail. TODO: have a better way to handle failure here - */ - WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); - - cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); - cpuset_update_task_spread_flags(cs, task); - } + cgroup_taskset_for_each(task, css, tset) + cpuset_attach_task(cs, task); /* * Change mm for all threadgroup leaders. This is expensive and may @@ -2948,11 +2953,28 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) */ static void cpuset_fork(struct task_struct *task) { - if (task_css_is_root(task, cpuset_cgrp_id)) + struct cpuset *cs; + bool same_cs; + + rcu_read_lock(); + cs = task_cs(task); + same_cs = (cs == task_cs(current)); + rcu_read_unlock(); + + if (same_cs) { + if (cs == &top_cpuset) + return; + + set_cpus_allowed_ptr(task, current->cpus_ptr); + task->mems_allowed = current->mems_allowed; return; + } - set_cpus_allowed_ptr(task, current->cpus_ptr); - task->mems_allowed = current->mems_allowed; + /* CLONE_INTO_CGROUP */ + percpu_down_write(&cpuset_rwsem); + guarantee_online_mems(cs, &cpuset_attach_nodemask_to); + cpuset_attach_task(cs, task); + percpu_up_write(&cpuset_rwsem); } struct cgroup_subsys cpuset_cgrp_subsys = { -- 2.31.1