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[23.128.96.18]) by mx.google.com with ESMTP id l12si2289822ejx.101.2020.11.20.11.20.14; Fri, 20 Nov 2020 11:20:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732276AbgKTTQp (ORCPT + 99 others); Fri, 20 Nov 2020 14:16:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:41418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732258AbgKTTQn (ORCPT ); Fri, 20 Nov 2020 14:16:43 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 308AD22240; Fri, 20 Nov 2020 19:16:41 +0000 (UTC) Date: Fri, 20 Nov 2020 14:16:39 -0500 From: Steven Rostedt To: Marco Elver Cc: "Paul E. McKenney" , Anders Roxell , Andrew Morton , Alexander Potapenko , Dmitry Vyukov , Jann Horn , Mark Rutland , Linux Kernel Mailing List , Linux-MM , kasan-dev , rcu@vger.kernel.org, Peter Zijlstra , Tejun Heo , Lai Jiangshan , linux-arm-kernel@lists.infradead.org Subject: Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...) Message-ID: <20201120141639.3896a3c8@gandalf.local.home> In-Reply-To: <20201120181737.GA3301774@elver.google.com> References: <20201118225621.GA1770130@elver.google.com> <20201118233841.GS1437@paulmck-ThinkPad-P72> <20201119125357.GA2084963@elver.google.com> <20201119151409.GU1437@paulmck-ThinkPad-P72> <20201119170259.GA2134472@elver.google.com> <20201119184854.GY1437@paulmck-ThinkPad-P72> <20201119193819.GA2601289@elver.google.com> <20201119213512.GB1437@paulmck-ThinkPad-P72> <20201120141928.GB3120165@elver.google.com> <20201120102613.3d18b90e@gandalf.local.home> <20201120181737.GA3301774@elver.google.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Nov 2020 19:17:37 +0100 Marco Elver wrote: > > > +++ b/kernel/rcu/Makefile > > > @@ -3,6 +3,13 @@ > > > # and is generally not a function of system call inputs. > > > KCOV_INSTRUMENT := n > > > > > > +ifdef CONFIG_FUNCTION_TRACER > > > +CFLAGS_REMOVE_update.o = $(CC_FLAGS_FTRACE) > > > +CFLAGS_REMOVE_sync.o = $(CC_FLAGS_FTRACE) > > > +CFLAGS_REMOVE_srcutree.o = $(CC_FLAGS_FTRACE) > > > +CFLAGS_REMOVE_tree.o = $(CC_FLAGS_FTRACE) > > > +endif > > > + > > > > Can you narrow it down further? That is, do you really need all of the > > above to stop the stalls? > > I tried to reduce it to 1 or combinations of 2 files only, but that > didn't work. I'm curious if this would help at all? diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2a52f42f64b6..d020ecefd151 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1094,7 +1094,7 @@ static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp) * if the current CPU is not in its idle loop or is in an interrupt or * NMI handler, return true. */ -bool rcu_is_watching(void) +notrace bool rcu_is_watching(void) { bool ret; Although I don't see it in the recursion list. -- Steve