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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL 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 5EB37C63777 for ; Fri, 20 Nov 2020 19:22:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AAEE8221F1 for ; Fri, 20 Nov 2020 19:22:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UoSVrsHF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AAEE8221F1 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A70016B0036; Fri, 20 Nov 2020 14:22:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A20EF6B005C; Fri, 20 Nov 2020 14:22:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E9DF6B005D; Fri, 20 Nov 2020 14:22:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0161.hostedemail.com [216.40.44.161]) by kanga.kvack.org (Postfix) with ESMTP id 6033F6B0036 for ; Fri, 20 Nov 2020 14:22:15 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0C3E3180AD82F for ; Fri, 20 Nov 2020 19:22:15 +0000 (UTC) X-FDA: 77505767430.29.self47_2300ff62734e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id DA593180A97E7 for ; Fri, 20 Nov 2020 19:22:14 +0000 (UTC) X-HE-Tag: self47_2300ff62734e X-Filterd-Recvd-Size: 5167 Received: from mail-oi1-f194.google.com (mail-oi1-f194.google.com [209.85.167.194]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Fri, 20 Nov 2020 19:22:14 +0000 (UTC) Received: by mail-oi1-f194.google.com with SMTP id t143so11638154oif.10 for ; Fri, 20 Nov 2020 11:22:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=x3bHHSoIiWnpt6sSCrh+oplbMynkFaA5raUA9UFenU8=; b=UoSVrsHFC/6ajfj53sIgq9KZJKGyJRjJagX2Jw9X+kmRK3eYNEjIDWo3EC7ORKCCpt hk/fUm411A5vkCbbI2r5PPlNm+uAaBCXyw5DDpdTbArnuiKB8R5jPukjeHq0yHn7JPuS FsYdW1mnUJGNGP9LYa6xm3+eTfwy/7XO2bHCZG4KcwKl84YjZ4USlMDjxaWiH1tG3yVm trknR40qepg10Ly4PsYPcJVI7J8g0G1SfqFziv1yGiS5O2RGR5vyrkrpXuBU5Qrs/2rq zFAen6YmbgB/hglU1e+oKw4WsXGUpwniG6CFV3YewJ7i2+mdR2ftYdEThiGPdxxaeKev 2IKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=x3bHHSoIiWnpt6sSCrh+oplbMynkFaA5raUA9UFenU8=; b=E/60rPex7CCr1qHYMM0sjnUOyMOuav0RoOH0QdfxQxYjqK+0XWgkVy+X8smwb/rmdP KhM+o0KqDUNQLJYRH/L+KGlXucBXImi0NK5cpt5IlDaleU3Ze1RzI4FW1w6vNidp17tk SmRApM/inl7M0BGHcHBBwRsliRfoyqv4Z0fbBYwqoo0E7OHpQkNVWifyxl9o5i5YIQvK /YEbVCxDvdALm/my6gn7EdSefgi49kSEVNfRZi+4QVLjoJNcZw2jQDx0nLutSx3Dq6se M69cz0KSAwqpwL8IZxrzubp67pjF8IaN8u12Ji+FG9cg0SZB9ACjAwrNVEFqCCVr8w1M 2KyQ== X-Gm-Message-State: AOAM530AItyxrsZgKJ8MRn21REAiHGSrMJFV+gIc6Ie9aj542exsTKOd 46jMP03nHjQDC51EcdbTvNQFFygiB0uI4gLkZTzaTw== X-Google-Smtp-Source: ABdhPJxOU8HRyWfOhXUizg1VIov+ux7MpOo8HRr290PtSWN/SNAM+kBbp9E9fBX8fCWm0czXOt58ykdlbb+3hS00UcU= X-Received: by 2002:a54:4681:: with SMTP id k1mr7597024oic.121.1605900133550; Fri, 20 Nov 2020 11:22:13 -0800 (PST) MIME-Version: 1.0 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> <20201120141639.3896a3c8@gandalf.local.home> In-Reply-To: <20201120141639.3896a3c8@gandalf.local.home> From: Marco Elver Date: Fri, 20 Nov 2020 20:22:01 +0100 Message-ID: Subject: Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...) To: Steven Rostedt 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 Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 20 Nov 2020 at 20:16, Steven Rostedt wrote: > > 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. It seems a patch to that effect is already in -next ("rcu,ftrace: Fix ftrace recursion"), and my experiments so far have all been with it. Thanks, -- Marco