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,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 CC656C55178 for ; Tue, 27 Oct 2020 12:00:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D10822281 for ; Tue, 27 Oct 2020 12:00:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="U40xokf4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750442AbgJ0MAH (ORCPT ); Tue, 27 Oct 2020 08:00:07 -0400 Received: from casper.infradead.org ([90.155.50.34]:39234 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750429AbgJ0MAG (ORCPT ); Tue, 27 Oct 2020 08:00:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=lOyYUi2UGQ8wMZn7t8xg/zlimJozkgepmx0I3u9L278=; b=U40xokf4yN2HeF5KRzSn4bLFgF QwjFROP+jrRyOYdyWLQrwOs7EYKwkDgwCh2eCji7h1trRrk+RORt0Vc7/ypjihry5E4hmUt5TeLXW 2uPMza5kiRcJ4BfKNXZtX2sOyTO4PKyIFL7YDUttHGFsOrymhPVOEasoZnvFQpi8jYvybkFBlDI7u Ze9F1Oy8yEuLgqa6JHonzJ2tmzgV0jTd98Wf7ehiS6iMf82lLC0YfBz+0B2Tr+1vK14t5nocIgMaT xDOpfICNxStJC7HB/Ix+ZVIjg0cW9IlLs/Q3UaWLXHqfDDtFpVHecCHyIvF/BqKpK1FxRIt2bxA1W iFFL848A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kXNdt-0007OI-BN; Tue, 27 Oct 2020 11:59:57 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id CE80B3006D0; Tue, 27 Oct 2020 12:59:55 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8B4BD203BE3F7; Tue, 27 Oct 2020 12:59:55 +0100 (CET) Date: Tue, 27 Oct 2020 12:59:55 +0100 From: Peter Zijlstra To: Chris Wilson Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, tip-bot2 for Peter Zijlstra , Qian Cai , x86 Subject: Re: [tip: locking/core] lockdep: Fix usage_traceoverflow Message-ID: <20201027115955.GA2611@hirez.programming.kicks-ass.net> References: <20200930094937.GE2651@hirez.programming.kicks-ass.net> <160208761332.7002.17400661713288945222.tip-bot2@tip-bot2> <160379817513.29534.880306651053124370@build.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <160379817513.29534.880306651053124370@build.alporthouse.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 27, 2020 at 11:29:35AM +0000, Chris Wilson wrote: > Quoting tip-bot2 for Peter Zijlstra (2020-10-07 17:20:13) > > The following commit has been merged into the locking/core branch of tip: > > > > Commit-ID: 24d5a3bffef117ed90685f285c6c9d2faa3a02b4 > > Gitweb: https://git.kernel.org/tip/24d5a3bffef117ed90685f285c6c9d2faa3a02b4 > > Author: Peter Zijlstra > > AuthorDate: Wed, 30 Sep 2020 11:49:37 +02:00 > > Committer: Peter Zijlstra > > CommitterDate: Wed, 07 Oct 2020 18:14:17 +02:00 > > > > lockdep: Fix usage_traceoverflow > > > > Basically print_lock_class_header()'s for loop is out of sync with the > > the size of of ->usage_traces[]. > > We're hitting a problem, > > $ cat /proc/lockdep_stats > > upon boot generates: > > [ 29.465702] DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused) > [ 29.465716] WARNING: CPU: 0 PID: 488 at kernel/locking/lockdep_proc.c:256 lockdep_stats_show+0xa33/0xac0 > > that bisected to this patch. Only just completed the bisection and > thought you would like a heads up. Oh hey, that's 'curious'... it does indeed trivially reproduce, let me have a poke.