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=-10.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 AB1F0C56201 for ; Fri, 20 Nov 2020 15:26:53 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1F007223BE for ; Fri, 20 Nov 2020 15:26:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YyKW+ruC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F007223BE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/zeRgr2aPs8KpQz3S81IK4KpzWrZwjtwINGxSqcTbfE=; b=YyKW+ruCzbqC6262gDaSeEG0W 4TuF7GvgKnYsCqKTZaM4YIR/dlDkLFGVgfxcyMCwP2UYJFBAYatneUydY3tuc9oSerbttzLo25PsE 5j43L+/14YumOKUoyocvFTiPSFpXcIWfa1wSTqASq5OOBAwIPSNtZRmOKoRvox2m3hnuQqtnlgqXc ZRMpuDCTobKcH5AzlV6bBj6wPnen5Ld7mw9/OChRjbKD9ZnWqE5hpDIb7jGWzOiXUlZv523f9RDuG 5nIKixUrd63AgmXlsfaho/QIsXLRha7StUQSxhWWC3CuyOOr+zocRwYfGM550Tl48rOZ2OQ9jFTvg N3KNk1ZKQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg8Io-0006H7-3i; Fri, 20 Nov 2020 15:26:22 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg8Ik-0006FQ-P3 for linux-arm-kernel@lists.infradead.org; Fri, 20 Nov 2020 15:26:19 +0000 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 80E0322252; Fri, 20 Nov 2020 15:26:15 +0000 (UTC) Date: Fri, 20 Nov 2020 10:26:13 -0500 From: Steven Rostedt To: Marco Elver Subject: Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...) Message-ID: <20201120102613.3d18b90e@gandalf.local.home> In-Reply-To: <20201120141928.GB3120165@elver.google.com> References: <20201117105236.GA1964407@elver.google.com> <20201117182915.GM1437@paulmck-ThinkPad-P72> <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> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201120_102618_901671_0C665967 X-CRM114-Status: GOOD ( 21.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Anders Roxell , "Paul E. McKenney" , Jann Horn , Peter Zijlstra , Lai Jiangshan , Linux Kernel Mailing List , kasan-dev , rcu@vger.kernel.org, Linux-MM , Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Tejun Heo , Andrew Morton , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 20 Nov 2020 15:19:28 +0100 Marco Elver wrote: > None of those triggered either. > > I found that disabling ftrace for some of kernel/rcu (see below) solved > the stalls (and any mention of deadlocks as a side-effect I assume), > resulting in successful boot. > > Does that provide any additional clues? I tried to narrow it down to 1-2 > files, but that doesn't seem to work. > > Thanks, > -- Marco > > ------ >8 ------ > > diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile > index 0cfb009a99b9..678b4b094f94 100644 > --- a/kernel/rcu/Makefile > +++ 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? Also, since you are using linux-next, you have ftrace recursion debugging. Please enable: CONFIG_FTRACE_RECORD_RECURSION=y CONFIG_RING_BUFFER_RECORD_RECURSION=y when enabling any of the above. If you can get to a successful boot, you can then: # cat /sys/kernel/tracing/recursed_functions Which would let me know if there's an recursion issue in RCU somewhere. -- Steve -- Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel