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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 DA90BC4338F for ; Fri, 30 Jul 2021 11:25:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C311E61050 for ; Fri, 30 Jul 2021 11:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238725AbhG3LZc (ORCPT ); Fri, 30 Jul 2021 07:25:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:36650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238712AbhG3LZY (ORCPT ); Fri, 30 Jul 2021 07:25:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2379E6101C; Fri, 30 Jul 2021 11:25:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627644319; bh=WAepL21rbrjFTc8SrzUcBXFOjwYdNAPaTXAlLZdQFdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fRDl5aUnYj4076IBQA1FmhVXpz1lWR0ifeC9iVcFXEqGhYTIOrfVEb8WKaLM0hZrs 8nasfVicG9X/R8r0UTrqjxQGVexRJzkxLLj9HakUQYWNMyBZGBIZopV2dveAGn98hp DEqDIGV9CKbSxcMWj2KbICdy0mskfKOhsWvzc8FGqXkCQNXgtg2C53jkpePrO8rENz ezUOijMz83fncmcdr4xt7oIPzG5xgWrFUH4oAuSxp0K6igcvFemC+5kFcZBgemLJyC o5nTgsah4cITIyQNoHxVGwwYLD9HgYbe5EP0zQ9vLjMaXeiLxeLSQ1zPLlpi2vSlHD lghg3IqatMzIQ== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com, Valentin Schneider Subject: [PATCH v11 07/16] sched: Split the guts of sched_setaffinity() into a helper function Date: Fri, 30 Jul 2021 12:24:34 +0100 Message-Id: <20210730112443.23245-8-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210730112443.23245-1-will@kernel.org> References: <20210730112443.23245-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for replaying user affinity requests using a saved mask, split sched_setaffinity() up so that the initial task lookup and security checks are only performed when the request is coming directly from userspace. Reviewed-by: Valentin Schneider Signed-off-by: Will Deacon --- kernel/sched/core.c | 105 ++++++++++++++++++++++++-------------------- 1 file changed, 57 insertions(+), 48 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a139ed8be7e3..d4219d366103 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7578,53 +7578,22 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, return retval; } -long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) +static int +__sched_setaffinity(struct task_struct *p, const struct cpumask *mask) { - cpumask_var_t cpus_allowed, new_mask; - struct task_struct *p; int retval; + cpumask_var_t cpus_allowed, new_mask; - rcu_read_lock(); - - p = find_process_by_pid(pid); - if (!p) { - rcu_read_unlock(); - return -ESRCH; - } - - /* Prevent p going away */ - get_task_struct(p); - rcu_read_unlock(); + if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) + return -ENOMEM; - if (p->flags & PF_NO_SETAFFINITY) { - retval = -EINVAL; - goto out_put_task; - } - if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { - retval = -ENOMEM; - goto out_put_task; - } if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { retval = -ENOMEM; goto out_free_cpus_allowed; } - retval = -EPERM; - if (!check_same_owner(p)) { - rcu_read_lock(); - if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { - rcu_read_unlock(); - goto out_free_new_mask; - } - rcu_read_unlock(); - } - - retval = security_task_setscheduler(p); - if (retval) - goto out_free_new_mask; - cpuset_cpus_allowed(p, cpus_allowed); - cpumask_and(new_mask, in_mask, cpus_allowed); + cpumask_and(new_mask, mask, cpus_allowed); /* * Since bandwidth control happens on root_domain basis, @@ -7645,23 +7614,63 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) #endif again: retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK); + if (retval) + goto out_free_new_mask; - if (!retval) { - cpuset_cpus_allowed(p, cpus_allowed); - if (!cpumask_subset(new_mask, cpus_allowed)) { - /* - * We must have raced with a concurrent cpuset - * update. Just reset the cpus_allowed to the - * cpuset's cpus_allowed - */ - cpumask_copy(new_mask, cpus_allowed); - goto again; - } + cpuset_cpus_allowed(p, cpus_allowed); + if (!cpumask_subset(new_mask, cpus_allowed)) { + /* + * We must have raced with a concurrent cpuset update. + * Just reset the cpumask to the cpuset's cpus_allowed. + */ + cpumask_copy(new_mask, cpus_allowed); + goto again; } + out_free_new_mask: free_cpumask_var(new_mask); out_free_cpus_allowed: free_cpumask_var(cpus_allowed); + return retval; +} + +long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) +{ + struct task_struct *p; + int retval; + + rcu_read_lock(); + + p = find_process_by_pid(pid); + if (!p) { + rcu_read_unlock(); + return -ESRCH; + } + + /* Prevent p going away */ + get_task_struct(p); + rcu_read_unlock(); + + if (p->flags & PF_NO_SETAFFINITY) { + retval = -EINVAL; + goto out_put_task; + } + + if (!check_same_owner(p)) { + rcu_read_lock(); + if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { + rcu_read_unlock(); + retval = -EPERM; + goto out_put_task; + } + rcu_read_unlock(); + } + + retval = security_task_setscheduler(p); + if (retval) + goto out_put_task; + + retval = __sched_setaffinity(p, in_mask); out_put_task: put_task_struct(p); return retval; -- 2.32.0.402.g57bb445576-goog