From patchwork Tue Jun 8 18:03:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12307873 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=-17.2 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 D781CC47082 for ; Tue, 8 Jun 2021 18:11:22 +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 A27A561246 for ; Tue, 8 Jun 2021 18:11:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A27A561246 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@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=ZYSZMAWrwiC3H2zXb2YU991Ob/w1OIobzx5eSzVSmlw=; b=G/RPM3ZJpV3wxA /PGikShbJJxfdur7KFXf+ZubuLPMDQfvj6CvIToAQVQbVufC7NyrGOFkSA2jUuwHLapCnaSfmlxKk fUSN00/UL1ux4CsynApYneBPHorbzHbTSQchQR7mPeMayluAeSt8dA2hlWWmxR+5Gog7jPRY5Lzxg gJ0dtvOI4I9Ra4Z1W9R7Klsywe6mY1RVcqYRn7WnCuekKNCq7NFMMlOyzprfpOBgEl9PqfrisZYvD bhOkGR6zyen+EJX1bzuDvcBDqRPSqGTlR6Xlorz2zpGX0Er3HLriucaZerJjgWEyOFKGeZMQZuAtA VvbczixbbHG6P7gF5nqg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqgAB-009tVg-3w; Tue, 08 Jun 2021 18:09:19 +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 1lqg5E-009qzj-Ii for linux-arm-kernel@lists.infradead.org; Tue, 08 Jun 2021 18:04:14 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 89D2D61377; Tue, 8 Jun 2021 18:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623175452; bh=UCK5EB6zz3DOsAavfWECWJwSJ41HPGa3wR9kNQ2PWw0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GMf985Vw18CY3ywHlFhB8D+8cjgDkQ031Sh8bK4t8k5qAUcfFnG9jQ63HacxdB/2W bBaw5WVUHuQ+7sdQ5uuKktFeBxNjZk4RYwLcjb5SJt7DQetuK+d0QuPVHEXDDGBUFs ozlnq4gam0e6VWQPnvPeK+1/PIHxxcBwFhaw91j4UVBVkQ6Mgb7UA/BXwwtczAwbUL 0hwMKDIzQ8SeOovoJPFpLq4tAoUhoHbbUxTrtM0iNO1BmqDYDxHU/F4yZtZ+Qx9+f1 nFqguvq/FTvq42wWcsHLUbhiCj+CMLACOHV9hw2P8UmhXQOhg7FHkOTFRcvTcmOu/H kjTc2tovQVh6g== 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 v9 11/20] sched: Split the guts of sched_setaffinity() into a helper function Date: Tue, 8 Jun 2021 19:03:04 +0100 Message-Id: <20210608180313.11502-12-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210608180313.11502-1-will@kernel.org> References: <20210608180313.11502-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_110412_698256_CDB49D3D X-CRM114-Status: GOOD ( 16.92 ) 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 f6ea3d7a07f2..d151446d5987 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6787,53 +6787,22 @@ 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, @@ -6854,23 +6823,63 @@ 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;