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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 39AA9C4321A for ; Fri, 28 Jun 2019 08:06:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 192B7208C4 for ; Fri, 28 Jun 2019 08:06:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726885AbfF1IG4 (ORCPT ); Fri, 28 Jun 2019 04:06:56 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:50399 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726828AbfF1IGr (ORCPT ); Fri, 28 Jun 2019 04:06:47 -0400 Received: by mail-wm1-f68.google.com with SMTP id c66so8126661wmf.0 for ; Fri, 28 Jun 2019 01:06:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=CCKTOX94dJMJaIi336ahfQwlG37S0yGGcCoKC+X5aD4=; b=D5fq92o5SRB81qL0haOeI9smb4BnjU2TdY2ryZb+IZv2zg1zoLHqDneXH+/WclNZpp zbHyquPL6IU/VQQ8PEY0fCJRnz7hKwF0c2xc6qa/BcGtTzs0YddLSeCUd+25TxbDya9v YoRNryGGgas2K3D9HAr3kydyO4vye250fwEzOvWWBBv+DAXe59YhrwDHttNNlah1SWtU vJZvB6fw1VPniefh4ySCC4LpFtkNSRxKQ1KUdYRi/iPMAeoXgCNRm0HTgGSNEuMHRv84 VqXB+90NgNrPLdFQ9rqll2Up+2cMRQDIgQSKu34mTyCH7mfaLQjVJebt5YkZvt0fZBhm wFBw== X-Gm-Message-State: APjAAAW5tmad+aqb6cPnC26cJSZ40F9dn1/+wlyEyXau/eEOehuJ/zAw JhWXPiuEMsVGVdZboSF8n48ksQ== X-Google-Smtp-Source: APXvYqzAsUT+533HfWPDIvW6mCpCh1TTKCdObNW67mDZ8ojUOZbvV3FebhVmYfJcgNWue1+BgE/Zyg== X-Received: by 2002:a1c:ef10:: with SMTP id n16mr5706288wmh.134.1561709205292; Fri, 28 Jun 2019 01:06:45 -0700 (PDT) Received: from localhost.localdomain.com ([151.29.165.245]) by smtp.gmail.com with ESMTPSA id z19sm1472774wmi.7.2019.06.28.01.06.43 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 28 Jun 2019 01:06:44 -0700 (PDT) From: Juri Lelli To: peterz@infradead.org, mingo@redhat.com, rostedt@goodmis.org, tj@kernel.org Cc: linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it, claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it, bristot@redhat.com, mathieu.poirier@linaro.org, lizefan@huawei.com, cgroups@vger.kernel.org, Juri Lelli Subject: [PATCH v8 8/8] rcu/tree: Setschedule gp ktread to SCHED_FIFO outside of atomic region Date: Fri, 28 Jun 2019 10:06:18 +0200 Message-Id: <20190628080618.522-9-juri.lelli@redhat.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190628080618.522-1-juri.lelli@redhat.com> References: <20190628080618.522-1-juri.lelli@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sched_setscheduler() needs to acquire cpuset_rwsem, but it is currently called from an invalid (atomic) context by rcu_spawn_gp_kthread(). Fix that by simply moving sched_setscheduler_nocheck() call outside of the atomic region, as it doesn't actually require to be guarded by rcu_node lock. Suggested-by: Peter Zijlstra Signed-off-by: Juri Lelli --- kernel/rcu/tree.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 980ca3ca643f..32ea75acba14 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3123,13 +3123,13 @@ static int __init rcu_spawn_gp_kthread(void) t = kthread_create(rcu_gp_kthread, NULL, "%s", rcu_state.name); if (WARN_ONCE(IS_ERR(t), "%s: Could not start grace-period kthread, OOM is now expected behavior\n", __func__)) return 0; + if (kthread_prio) + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); rnp = rcu_get_root(); raw_spin_lock_irqsave_rcu_node(rnp, flags); rcu_state.gp_kthread = t; - if (kthread_prio) { + if (kthread_prio) sp.sched_priority = kthread_prio; - sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); - } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); wake_up_process(t); rcu_spawn_nocb_kthreads(); -- 2.17.2