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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 546F0C433DF for ; Tue, 11 Aug 2020 16:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D9E820756 for ; Tue, 11 Aug 2020 16:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597162107; bh=YXBnDr9tWBPpWviVYK4o6ebIMUfUB+PCboBIK49UgUo=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=p8Vd40kNhFiXXS1oXgiLNk3XgB+sQPje1m3694BmLvD/BOKkK2Ik+m7AesXuTgjDR CW9Hi/3Rm2nS/81sn3H5SQpDiLNtYIHxb/3/Y7+WT95TofdxS6gDPcBhN/rEjv4uu+ FXeXuqORpl87/nkcOQOLsBgoJbsiaZdkhwieuFiQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729073AbgHKQI0 (ORCPT ); Tue, 11 Aug 2020 12:08:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:56944 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728797AbgHKQIZ (ORCPT ); Tue, 11 Aug 2020 12:08:25 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (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 A9F4D206B5; Tue, 11 Aug 2020 16:08:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597162104; bh=YXBnDr9tWBPpWviVYK4o6ebIMUfUB+PCboBIK49UgUo=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=af3H88W3v7EMMAKb7WaheEgqPqTKpQQbn3+BHd+EmRF76CyQrmvumehitO+OvC5sl CQlQRCFKJQHPIQAsKNY1JWS5wF3HfvaONAvjyU5s3ixEn5aG8xmHx4AfyZyyqaYVt0 HfhO2cshwrvMhRGzghktPwaBCdOvz2KXeu5K/Ccs= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 866C0352308E; Tue, 11 Aug 2020 09:08:24 -0700 (PDT) Date: Tue, 11 Aug 2020 09:08:24 -0700 From: "Paul E. McKenney" To: peterz@infradead.org Cc: Marco Elver , tglx@linutronix.de, mingo@kernel.org, will@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, rjw@rjwysocki.net Subject: Re: [RFC][PATCH 0/3] Tracing, Idle, RCU and such goodness Message-ID: <20200811160824.GY4295@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200807192336.405068898@infradead.org> <20200810095535.GA1597985@elver.google.com> <20200810121138.GV2674@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200810121138.GV2674@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 10, 2020 at 02:11:38PM +0200, peterz@infradead.org wrote: > On Mon, Aug 10, 2020 at 11:55:35AM +0200, Marco Elver wrote: > > > Unfortunately I get LOCKDEP_DEBUG warnings, when testing with one of > > syzbot's configs. This appears at some point during boot (no other > > test): > > > > DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled()) > > WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:4875 check_flags+0x52/0x200 kernel/locking/lockdep.c:4875 > > Modules linked in: > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0+ #8 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 > > RIP: 0010:check_flags+0x52/0x200 kernel/locking/lockdep.c:4875 > > Code: c0 74 48 e8 40 f7 a5 03 85 c0 74 20 83 3d bd 33 53 05 00 75 17 48 c7 c7 ce 12 c9 85 48 c7 c6 04 8c ca 85 31 c0 e8 4e c1 f7 ff <0f> 0b 48 c7 c7 db 8b ca 85 e9 8c 01 00 00 85 c0 75 0f 65 8b 05 c5 > > RSP: 0000:ffffffff86203bf0 EFLAGS: 00010046 > > RAX: 1f9fa70771052a00 RBX: 0000000000000000 RCX: ffffffff8627e980 > > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 > > RBP: 0000000000000000 R08: ffffffff813d8494 R09: 0000000000000000 > > R10: 0000000000000012 R11: ffffffff8627e980 R12: ffffffff8627e980 > > R13: ffffffff862e3420 R14: 00000000ffffffff R15: 0000000000000046 > > FS: 0000000000000000(0000) GS:ffff88881fa00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: ffff88883ffff000 CR3: 0000000006275001 CR4: 0000000000770ef0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > PKRU: 00000000 > > Call Trace: > > lock_is_held_type+0x4d/0x110 kernel/locking/lockdep.c:5043 > > lock_is_held include/linux/lockdep.h:266 [inline] > > rcu_read_lock_sched_held+0x41/0x90 kernel/rcu/update.c:136 > > trace_lock_acquire+0x49/0x120 include/trace/events/lock.h:13 > > lock_acquire+0x8d/0x2c0 kernel/locking/lockdep.c:5003 > > mutex_trylock+0xdd/0x120 kernel/locking/mutex.c:1420 > > *groan*, indeed! Which is the direct result of lockdep recursion because > we pulled that tracepoint out from under the recursion thing. > > Let me go prod this with a sharp stick... On the other hand, the first two commits in this series did pass weekend rcutorture testing. I clearly need to make rcutorture more viscious. ;-) But in the meantime, for the first two: Tested-by: Paul E. McKenney Thanx, Paul