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=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 27A92C4363A for ; Mon, 26 Oct 2020 11:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD53122265 for ; Mon, 26 Oct 2020 11:59:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="PKfyGuDI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1774585AbgJZL7c (ORCPT ); Mon, 26 Oct 2020 07:59:32 -0400 Received: from mx2.suse.de ([195.135.220.15]:39334 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1768805AbgJZL7c (ORCPT ); Mon, 26 Oct 2020 07:59:32 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1603713570; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gqulQtP8BApT2uUsXYPPjeATxjR9kCdGx0S8oTQNfDk=; b=PKfyGuDIvymAcXcce2412s4YMYLNQNn5GY4PDBvItTfzBZDN8PESOv8kpOcb6+HAvylWRX 0EWRqoavlFdvzM6aaRL0VqmyS/YS17IMyx6oiHnS8pE1kNNI/vSd+0s5A+7yc3naswgPIj f2UGzwFCGEfYFsd81/GOb1dbdavO+vI= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id ACB43AC8B; Mon, 26 Oct 2020 11:59:30 +0000 (UTC) Subject: Re: possible lockdep regression introduced by 4d004099a668 ("lockdep: Fix lockdep recursion") To: Jan Kara , Peter Zijlstra Cc: LKML , David Sterba References: <20201026114009.GN2594@hirez.programming.kicks-ass.net> <20201026115541.GC28769@quack2.suse.cz> From: Filipe Manana Message-ID: <546907be-1d9c-45c8-921e-6b7308648f18@suse.com> Date: Mon, 26 Oct 2020 11:59:29 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201026115541.GC28769@quack2.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/10/20 11:55, Jan Kara wrote: > On Mon 26-10-20 12:40:09, Peter Zijlstra wrote: >> On Mon, Oct 26, 2020 at 11:26:49AM +0000, Filipe Manana wrote: >>> Hello, >>> >>> I've recently started to hit a warning followed by tasks hanging after >>> attempts to freeze a filesystem. A git bisection pointed to the >>> following commit: >>> >>> commit 4d004099a668c41522242aa146a38cc4eb59cb1e >>> Author: Peter Zijlstra >>> Date: Fri Oct 2 11:04:21 2020 +0200 >>> >>> lockdep: Fix lockdep recursion >>> >>> This happens very reliably when running all xfstests with lockdep >>> enabled, and the tested filesystem is btrfs (haven't tried other >>> filesystems, but it shouldn't matter). The warning and task hangs always >>> happen at either test generic/068 or test generic/390, and (oddly) >>> always have to run all tests for it to trigger, running those tests >>> individually on an infinite loop doesn't seem to trigger it (at least >>> for a couple hours). >>> >>> The warning triggered is at fs/super.c:__sb_start_write() which always >>> results later in several tasks hanging on a percpu rw_sem: >>> >>> https://pastebin.com/qnLvf94E >>> >>> What happens is percpu_rwsem_is_held() is apparently returning a false >>> positive, >> >> That smells like the same issue reported here: >> >> https://lkml.kernel.org/r/20201022111700.GZ2651@hirez.programming.kicks-ass.net >> >> Make sure you have commit: >> >> f8e48a3dca06 ("lockdep: Fix preemption WARN for spurious IRQ-enable") >> >> (in Linus' tree by now) and do you have CONFIG_DEBUG_PREEMPT enabled? > > Hum, I am at 5.10-rc1 now and above mentioned commit doesn't appear to be > there? Also googling for the title doesn't help... Same here, can't find in Linus' tree neither through google. > > Honza >