Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753339Ab3FNN4i (ORCPT ); Fri, 14 Jun 2013 09:56:38 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:37336 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753173Ab3FNN4f (ORCPT ); Fri, 14 Jun 2013 09:56:35 -0400 From: "Rafael J. Wysocki" To: Jiang Liu Cc: Jiang Liu , Bjorn Helgaas , Yinghai Lu , "Alexander E . Patrakov" , Greg Kroah-Hartman , Yijing Wang , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , stable@vger.kernel.org Subject: Re: [BUGFIX 2/9] ACPIPHP: fix device destroying order issue when handling dock notification Date: Fri, 14 Jun 2013 16:05:48 +0200 Message-ID: <3541509.09EeuLnmd2@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.10.0-rc5+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <51BB2075.5040600@gmail.com> References: <1371141152-9468-1-git-send-email-jiang.liu@huawei.com> <2448481.HbOiE9Npmq@vostro.rjw.lan> <51BB2075.5040600@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3398 Lines: 76 On Friday, June 14, 2013 09:53:57 PM Jiang Liu wrote: > On 06/14/2013 03:59 AM, Rafael J. Wysocki wrote: > > On Friday, June 14, 2013 12:32:25 AM Jiang Liu wrote: > >> Current ACPI glue logic expects that physical devices are destroyed > >> before destroying companion ACPI devices, otherwise it will break the > >> ACPI unbind logic and cause following warning messages: > >> [ 185.026073] usb usb5: Oops, 'acpi_handle' corrupt > >> [ 185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt > >> [ 185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt > >> [ 180.013656] port1: Oops, 'acpi_handle' corrupt > >> Please refer to https://bugzilla.kernel.org/attachment.cgi?id=104321 > >> for full log message. > > > > So my question is, did we have this problem before commit 3b63aaa70e1? > > > > If we did, then when did it start? Or was it present forever? > I think this issue should exist before commit "PCI: acpiphp: Do not use > ACPI PCI subdriver mechanism". It may trace back to the changes to kill > acpi_pci_bind()/acpi_pci_unbind(). I thought so. > >> Above warning messages are caused by following scenario: > >> 1) acpi_dock_notifier_call() queues a task (T1) onto kacpi_hotplug_wq > >> 2) kacpi_hotplug_wq handles T1, which invokes acpi_dock_deferred_cb() > >> ->dock_notify()-> handle_eject_request()->hotplug_dock_devices() > >> 3) hotplug_dock_devices() first invokes registered hotplug callbacks to > >> destroy physical devices, then destroys all affected ACPI devices. > >> Everything seems perfect until now. But the acpiphp dock notification > >> handler will queue another task (T2) onto kacpi_hotplug_wq to really > >> destroy affected physical devices. > > > > Would not the solution be to modify it so that it didn't spawn the other > > task (T2), but removed the affected physical devices synchronously? > Yes, that's the way I'm going to fix this issue. > > > > >> 4) kacpi_hotplug_wq finishes T1, and all affected ACPI devices have > >> been destroyed. > >> 5) kacpi_hotplug_wq handles T2, which destroys all affected physical > >> devices. > >> > >> So it breaks ACPI glue logic's expection because ACPI devices are destroyed > >> in step 3 and physical devices are destroyed in step 5. > >> > >> Signed-off-by: Jiang Liu > >> Reported-by: Alexander E. Patrakov > >> Cc: Bjorn Helgaas > >> Cc: Yinghai Lu > >> Cc: "Rafael J. Wysocki" > >> Cc: linux-pci@vger.kernel.org > >> Cc: linux-kernel@vger.kernel.org > >> Cc: stable@vger.kernel.org > >> --- > >> Hi Bjorn and Rafael, > >> The recursive lock changes haven't been tested yet, need help > >> from Alexander for testing. > > > > Well, let's just say I'm not a fan of recursive locks. Is that unavoidable > > here? > Yeah, you are right, we encounter other deadlock issue here, as reported > by Alexander. So need to find new solution here. Can you please have a look at the patch I posted earlier in this thread? Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/