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 <jiang.liu@xxxxxxxxxx> > >> Reported-by: Alexander E. Patrakov <patrakov@xxxxxxxxx> > >> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > >> Cc: Yinghai Lu <yinghai@xxxxxxxxxx> > >> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> > >> Cc: linux-pci@xxxxxxxxxxxxxxx > >> Cc: linux-kernel@xxxxxxxxxxxxxxx > >> Cc: stable@xxxxxxxxxxxxxxx > >> --- > >> 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-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
