On 06/14/2013 08:23 PM, Rafael J. Wysocki wrote: > On Thursday, June 13, 2013 09:59:44 PM 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? >> >>> 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? >> >>> 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? > > What about the appended patch (on top of [1/9], untested)? > > Rafael It should have similar effect as patch 2/9, and it will encounter the same deadlock scenario as 2/9 too. > > > --- > drivers/pci/hotplug/acpiphp_glue.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c > =================================================================== > --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c > +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c > @@ -145,9 +145,20 @@ static int post_dock_fixups(struct notif > return NOTIFY_OK; > } > > +static void handle_dock_event_func(acpi_handle handle, u32 event, void *context) > +{ > + if (event == ACPI_NOTIFY_EJECT_REQUEST) { > + struct acpiphp_func *func = context; > + > + if (!acpiphp_disable_slot(func->slot)) > + acpiphp_eject_slot(func->slot); > + } else { > + handle_hotplug_event_func(handle, event, context); > + } > +} > > static const struct acpi_dock_ops acpiphp_dock_ops = { > - .handler = handle_hotplug_event_func, > + .handler = handle_dock_event_func, > }; > > /* Check whether the PCI device is managed by native PCIe hotplug driver */ > -- 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
