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 <ronald@innovation.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 416953a..b9fade7 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -1126,6 +1126,7 @@
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 7a34310..5008ead 100644
--- a/drivers/acpi/sbshc.c
+++ b/drivers/acpi/sbshc.c
@@ -196,6 +196,7 @@
hc->callback = NULL;
hc->context = NULL;
mutex_unlock(&hc->lock);
+ acpi_os_wait_events_complete();
return 0;
}
@@ -292,6 +293,7 @@
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;