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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 AE39FC3A5A8 for ; Sat, 31 Aug 2019 13:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8952723407 for ; Sat, 31 Aug 2019 13:03:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728316AbfHaNDV (ORCPT ); Sat, 31 Aug 2019 09:03:21 -0400 Received: from mga17.intel.com ([192.55.52.151]:54233 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726354AbfHaNDV (ORCPT ); Sat, 31 Aug 2019 09:03:21 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Aug 2019 06:03:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,451,1559545200"; d="scan'208";a="198237941" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by fmsmga001.fm.intel.com with SMTP; 31 Aug 2019 06:03:18 -0700 Received: by lahna (sSMTP sendmail emulation); Sat, 31 Aug 2019 16:03:17 +0300 Date: Sat, 31 Aug 2019 16:03:17 +0300 From: Mika Westerberg To: Dominik Brodowski Cc: andreas.noever@gmail.com, michael.jamet@intel.com, YehezkelShB@gmail.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: lockdep warning on thunderbolt docking Message-ID: <20190831130317.GL3177@lahna.fi.intel.com> References: <20190830125848.GA25929@owl.dominikbrodowski.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190830125848.GA25929@owl.dominikbrodowski.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dominik, On Fri, Aug 30, 2019 at 02:58:48PM +0200, Dominik Brodowski wrote: > When connecting a thunderbolt-enabled docking station to my work laptop, > the following lockdep warning is reported on v5.3.0-rc6+ as of Thursday > morning (can look up the exact git id if so required): Thanks for reporting. No need to dig for the commit ID. I'll take a look at this next week. > thunderbolt 0-1: new device found, vendor=0xd4 device=0xb070 > thunderbolt 0-1: Dell WD19TB Thunderbolt Dock > > ====================================================== > WARNING: possible circular locking dependency detected > 5.3.0-rc6+ #1 Tainted: G T > ------------------------------------------------------ > pool-/usr/lib/b/1258 is trying to acquire lock: > 000000005ab0ad43 (pci_rescan_remove_lock){+.+.}, at: authorized_store+0xe8/0x210 > > but task is already holding lock: > 00000000bfb796b5 (&tb->lock){+.+.}, at: authorized_store+0x7c/0x210 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #1 (&tb->lock){+.+.}: > __mutex_lock+0xac/0x9a0 > tb_domain_add+0x2d/0x130 > nhi_probe+0x1dd/0x330 > pci_device_probe+0xd2/0x150 > really_probe+0xee/0x280 > driver_probe_device+0x50/0xc0 > bus_for_each_drv+0x84/0xd0 > __device_attach+0xe4/0x150 > pci_bus_add_device+0x4e/0x70 > pci_bus_add_devices+0x2e/0x66 > pci_bus_add_devices+0x59/0x66 > pci_bus_add_devices+0x59/0x66 > enable_slot+0x344/0x450 > acpiphp_check_bridge.part.0+0x119/0x150 > acpiphp_hotplug_notify+0xaa/0x140 > acpi_device_hotplug+0xa2/0x3f0 > acpi_hotplug_work_fn+0x1a/0x30 > process_one_work+0x234/0x580 > worker_thread+0x50/0x3b0 > kthread+0x10a/0x140 > ret_from_fork+0x3a/0x50 > > -> #0 (pci_rescan_remove_lock){+.+.}: > __lock_acquire+0xe54/0x1ac0 > lock_acquire+0xb8/0x1b0 > __mutex_lock+0xac/0x9a0 > authorized_store+0xe8/0x210 > kernfs_fop_write+0x125/0x1b0 > vfs_write+0xc2/0x1d0 > ksys_write+0x6c/0xf0 > do_syscall_64+0x50/0x180 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > other info that might help us debug this: > Possible unsafe locking scenario: > CPU0 CPU1 > ---- ---- > lock(&tb->lock); > lock(pci_rescan_remove_lock); > lock(&tb->lock); > lock(pci_rescan_remove_lock); > > *** DEADLOCK *** > 5 locks held by pool-/usr/lib/b/1258: > #0: 000000003df1a1ad (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x4d/0x60 > #1: 0000000095a40b02 (sb_writers#6){.+.+}, at: vfs_write+0x185/0x1d0 > #2: 0000000017a7d714 (&of->mutex){+.+.}, at: kernfs_fop_write+0xf2/0x1b0 > #3: 000000004f262981 (kn->count#208){.+.+}, at: kernfs_fop_write+0xfa/0x1b0 > #4: 00000000bfb796b5 (&tb->lock){+.+.}, at: authorized_store+0x7c/0x210 > > stack backtrace: > CPU: 0 PID: 1258 Comm: pool-/usr/lib/b Tainted: G T 5.3.0-rc6+ #1 > > > Thanks, > Dominik