From patchwork Wed Jun 2 16:47:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12295365 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=-17.4 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 C0B75C4708F for ; Wed, 2 Jun 2021 16:54:06 +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 8A833619C3 for ; Wed, 2 Jun 2021 16:54:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A833619C3 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=uKEjwk8/+rSlXukQaHFIu01CBG7yPoddkpEFNj/NIV8=; b=PMBFnwlwUSMieB l9CwX7SEwj1sW2XOVykxeTiOgT33JkubicEz3TLXpCdg6sm+BEN5hUk3y/Aq2HEJLJskvCphNtGyH hCehEJx6MLt6olqDfJu3HPI+xqXhC2CUfe3LXv1FQbfNr4qvvewIF/KOtdfi6jyvNI73Mi6i6yUrz 77T+wiELgXSYpeS0H51S4DSTjr7V6S4CAyButcSOh13XB0k1f7E+h3kLmoupUhf7I38qtTdbXEwvt 5tqQy6249OjX8+TiIoL0v7tetz8PR4nEkE22mSevEYmd0D8BtiEXRDUTLmyagCkBrMQYwRYTJ63bK Kg6703De0i3l8OwwrfEQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1loU6P-005HKe-NY; Wed, 02 Jun 2021 16:52:22 +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 1loU2M-005FJK-Rx for linux-arm-kernel@lists.infradead.org; Wed, 02 Jun 2021 16:48:12 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 29E0161C2E; Wed, 2 Jun 2021 16:48:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622652490; bh=9xaWHZMgvDqWywCOxS0kboN6ePHSbsnyardY4msKEUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AEIswTyPnKxCUH1L8YEJy1ReM8GMw5N6BwmhRguK6ZbnyMx+D1PJYn2gmQxbwuZgh c0F4azxfk7eWPQ1PdcVkDMftAv0fiHBPTACWxaD4bgNVG/KDla7jCwxm4YpowChxe3 zBltgNCuQ8TKpd0MCxOpAhXfrY0a8OUiJUoWP++1LrHbifR9lkwMClBVbiKsih7BvV 6adsBPMMDwjUO7j+ZCBnToJFLHhn5s6lgBo2ly8eei9vsYDIhv97BQk1tvi2lG74f0 uCtPqhdKs0QEASCkv7hzy9awPKiNQL57Z/TSH4ntAE2TIT0f+jYZ29S0l7GUEbe2v1 9lnQHhTpBwlVg== 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 , kernel-team@android.com Subject: [PATCH v8 10/19] sched: Split the guts of sched_setaffinity() into a helper function Date: Wed, 2 Jun 2021 17:47:10 +0100 Message-Id: <20210602164719.31777-11-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210602164719.31777-1-will@kernel.org> References: <20210602164719.31777-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210602_094810_968196_C795977B X-CRM114-Status: GOOD ( 17.08 ) 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. Signed-off-by: Will Deacon Reviewed-by: Valentin Schneider --- 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 206e7bf95c79..f210d0b06944 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6788,53 +6788,22 @@ 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, @@ -6855,23 +6824,63 @@ 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;