From patchwork Fri Jul 30 11:24:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12411071 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=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 7F93DC4338F for ; Fri, 30 Jul 2021 11:28:36 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4429A6101C for ; Fri, 30 Jul 2021 11:28:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4429A6101C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=AitBC29os0ptxPiVlaqS6Fk0mBnB9tToq2shbQEgv1A=; b=d7mMdsANQ2w6+X vYhEJhbfgASam6epr+ynOeEZmsdiTdalILWAfS3jRpjv4BG/4HaS/sPf45z+MJ7D/MLAY/0HYj/vR qDwl15F+6tw7fZ4kSDBhFj5IMpocNO4T6UYM3vgsuWkmulwiubastcRrSvjH6VjaSDtg/wVYGlwP8 LxEWltHTzTYP6SV+K770wrhL3RXXXEmZqX7DrgloREeQXg4Ph3XAJO0zhy4AUXqPCo+8FahcE9d+0 D9Jp4OgpxLIK36bwJyr4+fwvfOsogaQR8UWqjGRytr3gL2VIBt47aLYf5Xhf6HMqkyY4zg35v1drg 2xAglKcG/MHz67JLs9rQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9QfN-008I46-PM; Fri, 30 Jul 2021 11:27:03 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9Qdk-008HSt-3k for linux-arm-kernel@lists.infradead.org; Fri, 30 Jul 2021 11:25:21 +0000 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210730_042520_228282_F41AD3D7 X-CRM114-Status: GOOD ( 17.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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;