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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 E1B5DC49ED6 for ; Wed, 11 Sep 2019 16:57:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFC50208E4 for ; Wed, 11 Sep 2019 16:57:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729551AbfIKQ5u (ORCPT ); Wed, 11 Sep 2019 12:57:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54498 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729028AbfIKQ5t (ORCPT ); Wed, 11 Sep 2019 12:57:49 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 63DA8A3719F; Wed, 11 Sep 2019 16:57:49 +0000 (UTC) Received: from t460p.redhat.com (ovpn-117-113.phx2.redhat.com [10.3.117.113]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F12A60C05; Wed, 11 Sep 2019 16:57:44 +0000 (UTC) From: Scott Wood To: Sebastian Andrzej Siewior Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, "Paul E . McKenney" , Joel Fernandes , Thomas Gleixner , Steven Rostedt , Peter Zijlstra , Juri Lelli , Clark Williams , Scott Wood Subject: [PATCH RT v3 3/5] sched: migrate_dis/enable: Use rt_invol_sleep Date: Wed, 11 Sep 2019 17:57:27 +0100 Message-Id: <20190911165729.11178-4-swood@redhat.com> In-Reply-To: <20190911165729.11178-1-swood@redhat.com> References: <20190911165729.11178-1-swood@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Wed, 11 Sep 2019 16:57:49 +0000 (UTC) Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Without this, rcu_note_context_switch() will complain if an RCU read lock is held when migrate_enable() calls stop_one_cpu(). Likewise when migrate_disable() calls pin_current_cpu() which calls __read_rt_lock() -- which bypasses the part of the mutex code that calls rt_invol_sleep_inc(). Signed-off-by: Scott Wood --- v3: Add to pin_current_cpu as well include/linux/sched.h | 4 ++-- kernel/cpu.c | 2 ++ kernel/rcu/tree_plugin.h | 2 +- kernel/sched/core.c | 4 ++++ 4 files changed, 9 insertions(+), 3 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index edc93b74f7d8..ecf5cbb23335 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -673,7 +673,7 @@ struct task_struct { int migrate_disable_atomic; # endif #endif -#ifdef CONFIG_PREEMPT_RT_FULL +#ifdef CONFIG_PREEMPT_RT_BASE /* Task is blocking due to RT-specific mechanisms, not voluntarily */ int rt_invol_sleep; #endif @@ -1882,7 +1882,7 @@ static __always_inline bool need_resched(void) return unlikely(tif_need_resched()); } -#ifdef CONFIG_PREEMPT_RT_FULL +#ifdef CONFIG_PREEMPT_RT_BASE static inline void rt_invol_sleep_inc(void) { current->rt_invol_sleep++; diff --git a/kernel/cpu.c b/kernel/cpu.c index 885a195dfbe0..32c6175b63b6 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -308,7 +308,9 @@ void pin_current_cpu(void) preempt_lazy_enable(); preempt_enable(); + rt_invol_sleep_inc(); __read_rt_lock(cpuhp_pin); + rt_invol_sleep_dec(); preempt_disable(); preempt_lazy_disable(); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 0da4b975cd71..6d92dafeeca5 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -292,7 +292,7 @@ void rcu_note_context_switch(bool preempt) barrier(); /* Avoid RCU read-side critical sections leaking down. */ trace_rcu_utilization(TPS("Start context switch")); lockdep_assert_irqs_disabled(); -#if defined(CONFIG_PREEMPT_RT_FULL) +#if defined(CONFIG_PREEMPT_RT_BASE) rt_invol = t->rt_invol_sleep; #endif WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !rt_invol); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e1bdd7f9be05..a151332474d8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7405,7 +7405,11 @@ void migrate_enable(void) unpin_current_cpu(); preempt_lazy_enable(); preempt_enable(); + + rt_invol_sleep_inc(); stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); + rt_invol_sleep_dec(); + return; } } -- 1.8.3.1