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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 684A2C10F14 for ; Thu, 3 Oct 2019 16:42:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D86520867 for ; Thu, 3 Oct 2019 16:42:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570120946; bh=Xyvrre4X+S8jYk7Ug49uysaicfimb21oXHG48XhPxd0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DYjZ4hiaxFPgLZAE8mDKRrUODLQ5cAfKkRXmMj46de0pa9/PKCQ+TFOM1xJikBr2+ 2+7i5okVESL25bHGsyJD9Gim7zomc9Rag/5qn/ve/a28sI7gOoqKP9I8ymAPHX4xgk OYAT3qylM65maUKG/Tg5azGuFF+Ru3QCwSp0HIeM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404417AbfJCQmZ (ORCPT ); Thu, 3 Oct 2019 12:42:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:53292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392630AbfJCQmU (ORCPT ); Thu, 3 Oct 2019 12:42:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D8A7F2245A; Thu, 3 Oct 2019 16:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570120939; bh=Xyvrre4X+S8jYk7Ug49uysaicfimb21oXHG48XhPxd0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=piniOYVvDXvemu50yb0Y429V22xi5/dHpO+JS2hPE6VYNItq6ZCSoM+GCL8TDaFPT UuN7V8JfTQtNDg02oRhMCEmNLYZo1I4j40mQZ3hTO23DF4ZsMYTvCUJjKGFQNuwjaV VhhIkS0z/nj5uE10uSWaqLCEXMllAKPiwVZT11+A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Dietmar Eggemann , Juri Lelli , Linus Torvalds , Thomas Gleixner , bristot@redhat.com, claudio@evidence.eu.com, lizefan@huawei.com, longman@redhat.com, luca.abeni@santannapisa.it, mathieu.poirier@linaro.org, rostedt@goodmis.org, tj@kernel.org, tommaso.cucinotta@santannapisa.it, Ingo Molnar , Sasha Levin Subject: [PATCH 5.3 067/344] rcu/tree: Call setschedule() gp ktread to SCHED_FIFO outside of atomic region Date: Thu, 3 Oct 2019 17:50:32 +0200 Message-Id: <20191003154546.721434354@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154540.062170222@linuxfoundation.org> References: <20191003154540.062170222@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Juri Lelli [ Upstream commit 1a763fd7c6335e3122c1cc09576ef6c99ada4267 ] 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 Tested-by: Dietmar Eggemann Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Thomas Gleixner Cc: bristot@redhat.com Cc: claudio@evidence.eu.com Cc: lizefan@huawei.com Cc: longman@redhat.com Cc: luca.abeni@santannapisa.it Cc: mathieu.poirier@linaro.org Cc: rostedt@goodmis.org Cc: tj@kernel.org Cc: tommaso.cucinotta@santannapisa.it Link: https://lkml.kernel.org/r/20190719140000.31694-8-juri.lelli@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- 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 a14e5fbbea467..eb764c24bc4d4 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3234,13 +3234,13 @@ 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(); -- 2.20.1