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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 D2576C43381 for ; Tue, 26 Mar 2019 17:49:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1D9E2084B for ; Tue, 26 Mar 2019 17:49:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732376AbfCZRtL (ORCPT ); Tue, 26 Mar 2019 13:49:11 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:39629 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729800AbfCZRtE (ORCPT ); Tue, 26 Mar 2019 13:49:04 -0400 Received: by mail-pg1-f196.google.com with SMTP id k3so4902616pga.6 for ; Tue, 26 Mar 2019 10:49:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=I/36I/sBQSfYQ3lZtoywK5bOl82kCXYlGgatLfZ9xzg=; b=iSy7nzEh3lqQcXwwqW2Vcngy56dgB6cZpNyD2jBEB8YU/XVF710qF74DKOJLjm8uRp sTMkZ2WW8FUsGlU1/jN/67BDlAdzXvjYQTfez1T8OTUAuWxKf7WBnUGwM7OITeOjpp6I k3e1Mwt7d6apQD4lnB/kH7whLxdq5MsVyh9sX1z5+Rn0sd3RO9XVhwEg1pgkF+XE2NrL yrQ6tEJ4P+45wh3wO7anPer1Uw7uNhaWh07DeoYDbNtV3CRb/K7J2ua5Ji/DjCLlD0C9 wCG1PqxuKw2KywGyLmefqlr+vAI3OmyHIwcW8sjHfwRR/4jeLqlch2cKnEDRT8xwer5n 3rmQ== X-Gm-Message-State: APjAAAXvTJkT+ktQ7pX+N0HxUXujf+xVAlqHZTXFh/2R8LrI2/KhWkIB L/ZlZWFh36FFLs9+sO4FVM4= X-Google-Smtp-Source: APXvYqw3TSdk1SBNbmrvNRFNJ2qRcNra2auhH0d+jVTnmzIzhPu5lcEka/XWAXijuXb7uEgWSBdkcg== X-Received: by 2002:a63:5b64:: with SMTP id l36mr30776381pgm.182.1553622543681; Tue, 26 Mar 2019 10:49:03 -0700 (PDT) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id b26sm22922766pgn.4.2019.03.26.10.49.02 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 26 Mar 2019 10:49:03 -0700 (PDT) Message-ID: <1553622542.118779.71.camel@acm.org> Subject: Re: "cat /proc/lockdep" after "rmmod " when !debug_locks will crash the system From: Bart Van Assche To: shenghui , peterz@infradead.org, mingo@redhat.com, will.deacon@arm.com, linux-kernel@vger.kernel.org Date: Tue, 26 Mar 2019 10:49:02 -0700 In-Reply-To: <1553622255.118779.69.camel@acm.org> References: <5c98a345.1c69fb81.21300.0be5SMTPIN_ADDED_BROKEN@mx.google.com> <1553527621.118779.2.camel@acm.org> <5c9973cc.1c69fb81.371e8.7b9fSMTPIN_ADDED_BROKEN@mx.google.com> <1553622255.118779.69.camel@acm.org> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-03-26 at 10:44 -0700, Bart Van Assche wrote: +AD4 On Tue, 2019-03-26 at 08:35 +-0800, shenghui wrote: +AD4 +AD4 My test steps: +AD4 +AD4 -------------- +AD4 +AD4 1) bootup the system, and check the calltrace in dmesg. Just warning and ignore it. +AD4 +AD4 2) cat /proc/lockdep +ACM everything is well +AD4 +AD4 3) rmmod some module which provides lock+AF8-class in lockdep +AD4 +AD4 In my system, module bcache is used: ('grep bcache /proc/lockdep' prints something) +AD4 +AD4 +ACo stop bcache set +AD4 +AD4 +ACo rmmod bcache +AD4 +AD4 I have tried other module, e.g: rmmod iwldvm +AD4 +AD4 4) cat /proc/lockdep +ACM system crash +AD4 +AD4 Hi shenghui, +AD4 +AD4 Thank you for having shared your test steps. I ran a slightly different test +AD4 myself: +AD4 +AD4 while true+ADs do cat /proc/lockdep +AD4-/dev/null+ADs done +ACY +AD4 (cd blktests +ACYAJg while ./check -q+ADs do :+ADs done) It seems like I hit +ACI-send+ACI too quickly. That test just triggered the following: BUG: unable to handle kernel paging request at fffffbfff40ca448 +ACM-PF error: +AFs-normal kernel read fault+AF0 PGD 13bfde067 P4D 13bfde067 PUD 13bf7a067 PMD 1167d3067 PTE 0 Oops: 0000 +AFsAIw-1+AF0 PREEMPT SMP KASAN CPU: 4 PID: 4529 Comm: cat Tainted: G B W O 5.1.0-rc1-dbg+- +ACM-4 Hardware name: QEMU Standard PC (i440FX +- PIIX, 1996), BIOS 1.10.2-1 04/01/2014 RIP: 0010:+AF8AXw-asan+AF8-load1+-0x28/0x50 Call Trace: string+-0xac/0x180 vsnprintf+-0x23e/0x820 seq+AF8-vprintf+-0x82/0xc0 seq+AF8-printf+-0x92/0xb0 print+AF8-name+-0x34/0xb0 l+AF8-show+-0x184/0x200 seq+AF8-read+-0x59e/0x6c0 proc+AF8-reg+AF8-read+-0x11f/0x170 +AF8AXw-vfs+AF8-read+-0x4d/0x90 vfs+AF8-read+-0xc5/0x1f0 ksys+AF8-read+-0xab/0x130 +AF8AXw-x64+AF8-sys+AF8-read+-0x43/0x50 do+AF8-syscall+AF8-64+-0x71/0x210 entry+AF8-SYSCALL+AF8-64+AF8-after+AF8-hwframe+-0x49/0xbe I will have a closer look at this. Bart.