From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E51793019C8 for ; Sun, 21 Jun 2026 03:29:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782012559; cv=none; b=NhEGEtAPr5NkZuxZAp9jYSx2rv9vMkxRdGyofYt4XBEzDJ6N+l38mF+fDMsA9XJO9HyS/4CqXzFPTs/VV6F3rxBJgVViNACYjw/ItrVKfqahsmQmXUx85LW/rL6xKwpyFUpWuCgL74j/1GqHhhR3amgPbsHkLQq/Frq30X3lFIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782012559; c=relaxed/simple; bh=/we5puykqdoiyalGPloOcLI5knOGUqsw88iPz9JkyZQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mtHPWokLmp/cMVdOq1iukcdW5goynF89ykwacuHzC0kv8rF9JcPoBCSqSp362XTNU6lzvXnZiz3itmxiCpAC8A0au8PmREHTZxvtIlcOTZuTfx1VckG0N5AYdHVQgp8Q5uFF9FzjXd/cpV++vwlJr9WtKJYkXxp0Qjn0vNy5eKM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aSghJv1B; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aSghJv1B" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782012557; 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=KUwBC06+cbgbFAXUy9wTqsbvmrhAJxN7zFgKwurRmec=; b=aSghJv1BlcPhL9alSC6ZqNHoT2V61qTn3PI4O6k8gTuwlCp03pN7Vq+a306AYrqD1tqvqM JhEJWhOqtaEDdmWCli6Nj2SMBMaxuVHhJ5AGf6Q0fuxn3Iy97j0wbQ6hMNtoX/5QCluZCT 5yAzpjxfIXPQj7BIjZLbwiPF5KN3hVk= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-608-P4oyMuNdNPyVenx9lXC8Xg-1; Sat, 20 Jun 2026 23:29:11 -0400 X-MC-Unique: P4oyMuNdNPyVenx9lXC8Xg-1 X-Mimecast-MFC-AGG-ID: P4oyMuNdNPyVenx9lXC8Xg_1782012549 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 560E1195605F; Sun, 21 Jun 2026 03:29:09 +0000 (UTC) Received: from llong-thinkpadp16vgen1.westford.csb (unknown [10.22.88.8]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 43F7B195604D; Sun, 21 Jun 2026 03:29:07 +0000 (UTC) From: Waiman Long To: Ridong Chen , Tejun Heo , Johannes Weiner , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Li Zefan , Farhad Alemi , Andrew Morton Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Aaron Tomlin , Guopeng Zhang , Gregory Price , David Hildenbrand , Waiman Long Subject: [PATCH v7 5/9] cgroup/cpuset: Expand the scope of cpuset_can_attach_check() Date: Sat, 20 Jun 2026 23:28:12 -0400 Message-ID: <20260621032816.1806773-6-longman@redhat.com> In-Reply-To: <20260621032816.1806773-1-longman@redhat.com> References: <20260621032816.1806773-1-longman@redhat.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Expand the scope of cpuset_can_attach_check() by including the setting of setsched flag inside cpuset_can_attach_check() with the new @oldcs and @psetsched argument. As cpuset_can_attach_check() is also called from cpuset_can_fork(), set the new arguments to NULL from that caller. Reviewed-by: Ridong Chen Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 52 ++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 22 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2ffc66baedf3..b7b5072f2fdd 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2985,12 +2985,39 @@ static struct cpuset *cpuset_attach_old_cs; * For v1, cpus_allowed and mems_allowed can't be empty. * For v2, effective_cpus can't be empty. * Note that in v1, effective_cpus = cpus_allowed. + * + * Also set the boolean flag passed in by @psetsched depending on if + * security_task_setscheduler() call is needed and @oldcs is not NULL. */ -static int cpuset_can_attach_check(struct cpuset *cs) +static int cpuset_can_attach_check(struct cpuset *cs, struct cpuset *oldcs, + bool *psetsched) { if (cpumask_empty(cs->effective_cpus) || (!is_in_v2_mode() && nodes_empty(cs->mems_allowed))) return -ENOSPC; + + if (!oldcs) + return 0; + + /* + * Skip rights over task setsched check in v2 when nothing changes, + * migration permission derives from hierarchy ownership in + * cgroup_procs_write_permission()). + */ + *psetsched = !cpuset_v2() || + !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus) || + !nodes_equal(cs->effective_mems, oldcs->effective_mems); + + /* + * A v1 cpuset with tasks will have no CPU left only when CPU hotplug + * brings the last online CPU offline as users are not allowed to empty + * cpuset.cpus when there are active tasks inside. When that happens, + * we should allow tasks to migrate out without security check to make + * sure they will be able to run after migration. + */ + if (!is_in_v2_mode() && cpumask_empty(oldcs->effective_cpus)) + *psetsched = false; + return 0; } @@ -3037,29 +3064,10 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ - ret = cpuset_can_attach_check(cs); + ret = cpuset_can_attach_check(cs, oldcs, &setsched_check); if (ret) goto out_unlock; - /* - * Skip rights over task setsched check in v2 when nothing changes, - * migration permission derives from hierarchy ownership in - * cgroup_procs_write_permission()). - */ - setsched_check = !cpuset_v2() || - !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus) || - !nodes_equal(cs->effective_mems, oldcs->effective_mems); - - /* - * A v1 cpuset with tasks will have no CPU left only when CPU hotplug - * brings the last online CPU offline as users are not allowed to empty - * cpuset.cpus when there are active tasks inside. When that happens, - * we should allow tasks to migrate out without security check to make - * sure they will be able to run after migration. - */ - if (!is_in_v2_mode() && cpumask_empty(oldcs->effective_cpus)) - setsched_check = false; - cgroup_taskset_for_each(task, css, tset) { ret = task_can_attach(task); if (ret) @@ -3616,7 +3624,7 @@ static int cpuset_can_fork(struct task_struct *task, struct css_set *cset) mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ - ret = cpuset_can_attach_check(cs); + ret = cpuset_can_attach_check(cs, NULL, NULL); if (ret) goto out_unlock; -- 2.54.0