On Monday, October 1, 2018 4:53:13 AM CEST Ronald Tschalär wrote:
> There was a small race when removing the sbshc module where
> smbus_alarm() had queued acpi_smbus_callback() for deferred execution
> but it hadn't been run yet, so that when it did run hc had been freed
> and the module unloaded, resulting in an invalid paging request.
>
> A similar race existed when removing the sbs module with regards to
> acpi_sbs_callback() (which is called from acpi_smbus_callback()).
>
> We therefore need to ensure no callbacks are pending or executing before
> the cleanups are done and the modules are removed.
>
> Signed-off-by: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
> ---
> drivers/acpi/osl.c | 1 +
> drivers/acpi/sbshc.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 8df9abfa947b..9d139727f164 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -1129,6 +1129,7 @@ void acpi_os_wait_events_complete(void)
> flush_workqueue(kacpid_wq);
> flush_workqueue(kacpi_notify_wq);
> }
> +EXPORT_SYMBOL(acpi_os_wait_events_complete);
>
> struct acpi_hp_work {
> struct work_struct work;
> diff --git a/drivers/acpi/sbshc.c b/drivers/acpi/sbshc.c
> index 7a3431018e0a..5008ead4609a 100644
> --- a/drivers/acpi/sbshc.c
> +++ b/drivers/acpi/sbshc.c
> @@ -196,6 +196,7 @@ int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
> hc->callback = NULL;
> hc->context = NULL;
> mutex_unlock(&hc->lock);
> + acpi_os_wait_events_complete();
> return 0;
> }
>
> @@ -292,6 +293,7 @@ static int acpi_smbus_hc_remove(struct acpi_device *device)
>
> hc = acpi_driver_data(device);
> acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
> + acpi_os_wait_events_complete();
> kfree(hc);
> device->driver_data = NULL;
> return 0;
>
Applied, thanks!
