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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 26491C2D0E4 for ; Mon, 23 Nov 2020 19:32:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A50E320637 for ; Mon, 23 Nov 2020 19:32:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A50E320637 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C91E6B005D; Mon, 23 Nov 2020 14:32:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 078326B006E; Mon, 23 Nov 2020 14:32:53 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E34DC6B0070; Mon, 23 Nov 2020 14:32:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0089.hostedemail.com [216.40.44.89]) by kanga.kvack.org (Postfix) with ESMTP id B42806B005D for ; Mon, 23 Nov 2020 14:32:52 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 390A83636 for ; Mon, 23 Nov 2020 19:32:52 +0000 (UTC) X-FDA: 77516680584.07.back08_090ba2f27367 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 19C731803F9A2 for ; Mon, 23 Nov 2020 19:32:52 +0000 (UTC) X-HE-Tag: back08_090ba2f27367 X-Filterd-Recvd-Size: 4161 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 23 Nov 2020 19:32:51 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 97DE4101E; Mon, 23 Nov 2020 11:32:50 -0800 (PST) Received: from C02TD0UTHF1T.local (unknown [10.57.27.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DDCC93F71F; Mon, 23 Nov 2020 11:32:46 -0800 (PST) Date: Mon, 23 Nov 2020 19:32:41 +0000 From: Mark Rutland To: Marco Elver Cc: Will Deacon , "Paul E. McKenney" , Steven Rostedt , Anders Roxell , Andrew Morton , Alexander Potapenko , Dmitry Vyukov , Jann Horn , 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: <20201123193241.GA45639@C02TD0UTHF1T.local> References: <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> <20201119225352.GA5251@willie-the-truck> <20201120103031.GB2328@C02TD0UTHF1T.local> <20201120140332.GA3120165@elver.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120140332.GA3120165@elver.google.com> 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, Nov 20, 2020 at 03:03:32PM +0100, Marco Elver wrote: > On Fri, Nov 20, 2020 at 10:30AM +0000, Mark Rutland wrote: > > On Thu, Nov 19, 2020 at 10:53:53PM +0000, Will Deacon wrote: > > > FWIW, arm64 is known broken wrt lockdep and irq tracing atm. Mark has been > > > looking at that and I think he is close to having something workable. > > > > > > Mark -- is there anything Marco and Paul can try out? > > > > I initially traced some issues back to commit: > > > > 044d0d6de9f50192 ("lockdep: Only trace IRQ edges") > > > > ... and that change of semantic could cause us to miss edges in some > > cases, but IIUC mostly where we haven't done the right thing in > > exception entry/return. > > > > I don't think my patches address this case yet, but my WIP (currently > > just fixing user<->kernel transitions) is at: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/irq-fixes > > > > I'm looking into the kernel<->kernel transitions now, and I know that we > > mess up RCU management for a small window around arch_cpu_idle, but it's > > not immediately clear to me if either of those cases could cause this > > report. > > Thank you -- I tried your irq-fixes, however that didn't seem to fix the > problem (still get warnings and then a panic). :-/ I've just updated that branch with a new version which I hope covers kernel<->kernel transitions too. If you get a chance, would you mind giving that a spin? The HEAD commit should be: a51334f033f8ee88 ("HACK: check IRQ tracing has RCU watching") Otherwise, I intend to clean that up and post it tomorrow (without the additional debug hacks). I've thrown my local Syzkaller instance at it in the mean time (and if I get the chance tomrrow I'll try to get rcutorture setup), and the only report I'm seeing so far looks genuine: | BUG: sleeping function called from invalid context in sta_info_move_state ... as that was reported on x86 too, per: https://syzkaller.appspot.com/bug?id=6c7899acf008be2ddcddb46a2567c2153193632a Thanks, Mark.