Re: [BUGFIX v2 3/4] PCI, ACPI: fix device destroying order issue whenhandling dock notification

[Yinghai Lu]

On Fri, Jun 14, 2013 at 12:28 PM, Jiang Liu <jiang.liu@xxxxxxxxxx> 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.
>
> 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.
> 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 # 3.8+

Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>

> ---
>  drivers/pci/hotplug/acpiphp_glue.c | 32 ++++++++++++++++++--------------
>  1 file changed, 18 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 5d696f5..a65203b 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -61,6 +61,8 @@ static DEFINE_MUTEX(bridge_mutex);
>  static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
>  static void acpiphp_sanitize_bus(struct pci_bus *bus);
>  static void acpiphp_set_hpp_values(struct pci_bus *bus);
> +static void _handle_hotplug_event_func(acpi_handle handle, u32 type,
> +                                      void *context);
>  static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
>  static void free_bridge(struct kref *kref);
>
> @@ -160,7 +162,7 @@ static void acpiphp_dock_put(void *data)
>  }
>
>  static const struct acpi_dock_ops acpiphp_dock_ops = {
> -       .handler = handle_hotplug_event_func,
> +       .handler = _handle_hotplug_event_func,
>         .get = acpiphp_dock_get,
>         .put = acpiphp_dock_put,
>  };
> @@ -1080,22 +1082,13 @@ static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,
>         alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_bridge);
>  }
>
> -static void _handle_hotplug_event_func(struct work_struct *work)
> +static void _handle_hotplug_event_func(acpi_handle handle, u32 type,
> +                                      void *context)
>  {
> -       struct acpiphp_func *func;
> +       struct acpiphp_func *func = context;
>         char objname[64];
>         struct acpi_buffer buffer = { .length = sizeof(objname),
>                                       .pointer = objname };
> -       struct acpi_hp_work *hp_work;
> -       acpi_handle handle;
> -       u32 type;
> -
> -       hp_work = container_of(work, struct acpi_hp_work, work);
> -       handle = hp_work->handle;
> -       type = hp_work->type;
> -       func = (struct acpiphp_func *)hp_work->context;
> -
> -       acpi_scan_lock_acquire();
>
>         acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
>
> @@ -1128,7 +1121,18 @@ static void _handle_hotplug_event_func(struct work_struct *work)
>                 warn("notify_handler: unknown event type 0x%x for %s\n", type, objname);
>                 break;
>         }
> +}
> +
> +static void _handle_hotplug_event_cb(struct work_struct *work)
> +{
> +       struct acpiphp_func *func;
> +       struct acpi_hp_work *hp_work;
>
> +       hp_work = container_of(work, struct acpi_hp_work, work);
> +       func = (struct acpiphp_func *)hp_work->context;
> +       acpi_scan_lock_acquire();
> +       _handle_hotplug_event_func(hp_work->handle, hp_work->type,
> +                                   hp_work->context);
>         acpi_scan_lock_release();
>         kfree(hp_work); /* allocated in handle_hotplug_event_func */
>         put_bridge(func->slot->bridge);
> @@ -1156,7 +1160,7 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type,
>          * don't deadlock on hotplug actions.
>          */
>         get_bridge(func->slot->bridge);
> -       alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);
> +       alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_cb);
>  }
>
>  /*
> --
> 1.8.1.2
>
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