From: Ronald Tschalär Date: Mon, 1 Oct 2018 02:53:13 +0000 (-0700) Subject: ACPI / SBS: Fix rare oops when removing modules X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2b6440486cc363d004be237b23c90f346506f1d7;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git ACPI / SBS: Fix rare oops when removing modules [ Upstream commit 757c968c442397f1249bb775a7c8c03842e3e0c7 ] 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 Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 416953a42510..b9fade7a3bcf 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -1126,6 +1126,7 @@ 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;