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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 35327C4332D for ; Wed, 6 Jan 2021 00:58:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 193DA229EF for ; Wed, 6 Jan 2021 00:58:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727034AbhAFA6W (ORCPT ); Tue, 5 Jan 2021 19:58:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:55912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725925AbhAFA6T (ORCPT ); Tue, 5 Jan 2021 19:58:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 44D7622E03; Wed, 6 Jan 2021 00:57:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609894658; bh=7Lpg3JpvCyhFmK3955GjHbz3mWVxQeMM9a2XxyDeSik=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l8guUJy78crW8ihMo2D0KzOV8nxIWDkqrYd9YCa8nxGBo5f36mqilxn1Hunovpxt4 WLIbX/QK3i6c75US+SS+vfSsVOrJwu2TGd6fiHnixXUMHpAlhFXUGpZmn7Qnf4oqXy 5lMSMEaeWGOdPHxJfX9jDWpmhq2zL9yEMNJVbvi7R/2/8+hqqX6lU1JyQeRhWr9IZO XzclKNrCIa3ARmHfEyapEXoLTLbndB3lNqMp/iN6wj9yEhOMNtig4aMVKXd+oU6yOj 69+AA1Myq9ANDBXG8ZbdXGLvBT9RQp8PevgIcuj/ZwXfG83g4C6TbNCSiUcwpms//D w2/OpZFre+hSQ== From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 3/6] rcu: Add lockdep_assert_irqs_disabled() to rcu_sched_clock_irq() and callees Date: Tue, 5 Jan 2021 16:57:33 -0800 Message-Id: <20210106005736.12613-3-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20210106005713.GA12492@paulmck-ThinkPad-P72> References: <20210106005713.GA12492@paulmck-ThinkPad-P72> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" This commit adds a number of lockdep_assert_irqs_disabled() calls to rcu_sched_clock_irq() and a number of the functions that it calls. The point of this is to help track down a situation where lockdep appears to be insisting that interrupts are enabled within these functions, which should only ever be invoked from the scheduling-clock interrupt handler. Link: https://lore.kernel.org/lkml/20201111133813.GA81547@elver.google.com/ Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 4 ++++ kernel/rcu/tree_plugin.h | 1 + kernel/rcu/tree_stall.h | 8 ++++++++ 3 files changed, 13 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index bd04b09..f70634f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2553,6 +2553,7 @@ static void rcu_do_batch(struct rcu_data *rdp) void rcu_sched_clock_irq(int user) { trace_rcu_utilization(TPS("Start scheduler-tick")); + lockdep_assert_irqs_disabled(); raw_cpu_inc(rcu_data.ticks_this_gp); /* The load-acquire pairs with the store-release setting to true. */ if (smp_load_acquire(this_cpu_ptr(&rcu_data.rcu_urgent_qs))) { @@ -2566,6 +2567,7 @@ void rcu_sched_clock_irq(int user) rcu_flavor_sched_clock_irq(user); if (rcu_pending(user)) invoke_rcu_core(); + lockdep_assert_irqs_disabled(); trace_rcu_utilization(TPS("End scheduler-tick")); } @@ -3690,6 +3692,8 @@ static int rcu_pending(int user) struct rcu_data *rdp = this_cpu_ptr(&rcu_data); struct rcu_node *rnp = rdp->mynode; + lockdep_assert_irqs_disabled(); + /* Check for CPU stalls, if enabled. */ check_cpu_stall(rdp); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index fd8a52e..cb76e70 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -682,6 +682,7 @@ static void rcu_flavor_sched_clock_irq(int user) { struct task_struct *t = current; + lockdep_assert_irqs_disabled(); if (user || rcu_is_cpu_rrupt_from_idle()) { rcu_note_voluntary_context_switch(current); } diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index ca21d28..4024dcc 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -260,6 +260,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags) struct task_struct *t; struct task_struct *ts[8]; + lockdep_assert_irqs_disabled(); if (!rcu_preempt_blocked_readers_cgp(rnp)) return 0; pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):", @@ -284,6 +285,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags) ".q"[rscr.rs.b.need_qs], ".e"[rscr.rs.b.exp_hint], ".l"[rscr.on_blkd_list]); + lockdep_assert_irqs_disabled(); put_task_struct(t); ndetected++; } @@ -472,6 +474,8 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) struct rcu_node *rnp; long totqlen = 0; + lockdep_assert_irqs_disabled(); + /* Kick and suppress, if so configured. */ rcu_stall_kick_kthreads(); if (rcu_stall_is_suppressed()) @@ -493,6 +497,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) } } ndetected += rcu_print_task_stall(rnp, flags); // Releases rnp->lock. + lockdep_assert_irqs_disabled(); } for_each_possible_cpu(cpu) @@ -538,6 +543,8 @@ static void print_cpu_stall(unsigned long gps) struct rcu_node *rnp = rcu_get_root(); long totqlen = 0; + lockdep_assert_irqs_disabled(); + /* Kick and suppress, if so configured. */ rcu_stall_kick_kthreads(); if (rcu_stall_is_suppressed()) @@ -592,6 +599,7 @@ static void check_cpu_stall(struct rcu_data *rdp) unsigned long js; struct rcu_node *rnp; + lockdep_assert_irqs_disabled(); if ((rcu_stall_is_suppressed() && !READ_ONCE(rcu_kick_kthreads)) || !rcu_gp_in_progress()) return; -- 2.9.5