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 ECC52C3A5A7 for ; Fri, 30 Aug 2019 13:05:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD10121897 for ; Fri, 30 Aug 2019 13:05:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727948AbfH3NFW (ORCPT ); Fri, 30 Aug 2019 09:05:22 -0400 Received: from isilmar-4.linta.de ([136.243.71.142]:60068 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727417AbfH3NFV (ORCPT ); Fri, 30 Aug 2019 09:05:21 -0400 X-Greylist: delayed 372 seconds by postgrey-1.27 at vger.kernel.org; Fri, 30 Aug 2019 09:05:20 EDT X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES Received: from owl.dominikbrodowski.net (owl-tcp.brodo.linta [10.1.0.111]) by isilmar-4.linta.de (Postfix) with ESMTPSA id 2A1C02006F1; Fri, 30 Aug 2019 12:59:01 +0000 (UTC) Received: by owl.dominikbrodowski.net (Postfix, from userid 1000) id 21948807E2; Fri, 30 Aug 2019 14:58:48 +0200 (CEST) Date: Fri, 30 Aug 2019 14:58:48 +0200 From: Dominik Brodowski To: andreas.noever@gmail.com, michael.jamet@intel.com, mika.westerberg@linux.intel.com, YehezkelShB@gmail.com, bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: lockdep warning on thunderbolt docking Message-ID: <20190830125848.GA25929@owl.dominikbrodowski.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 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): 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