ACPI/PCI: Fix possible race condition on _OSC evaluation
Fix possible race condition on _OSC evaluation.
Current _OSC evaluation code has possible race condition because it
maniputes osc_data linked list or its contents without any lock
mechanism.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 89a2f0f..14848bf 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -35,6 +35,8 @@
u32 query_result;
};
+static DEFINE_MUTEX(pci_acpi_lock);
+
static struct acpi_osc_data *acpi_get_osc_data(acpi_handle handle)
{
struct acpi_osc_data *data;
@@ -131,10 +133,12 @@
if (ACPI_FAILURE(status))
return status;
+ mutex_lock(&pci_acpi_lock);
osc_data = acpi_get_osc_data(handle);
if (!osc_data) {
printk(KERN_ERR "acpi osc data array is full\n");
- return AE_ERROR;
+ status = AE_ERROR;
+ goto out;
}
/* do _OSC query for all possible controls */
@@ -149,7 +153,8 @@
osc_data->query_result = osc_args.query_result;
osc_data->is_queried = 1;
}
-
+out:
+ mutex_unlock(&pci_acpi_lock);
return status;
}
@@ -190,19 +195,25 @@
if (ACPI_FAILURE(status))
return status;
+ mutex_lock(&pci_acpi_lock);
osc_data = acpi_get_osc_data(handle);
if (!osc_data) {
printk(KERN_ERR "acpi osc data array is full\n");
- return AE_ERROR;
+ status = AE_ERROR;
+ goto out;
}
ctrlset = (flags & OSC_CONTROL_MASKS);
- if (!ctrlset)
- return AE_TYPE;
+ if (!ctrlset) {
+ status = AE_TYPE;
+ goto out;
+ }
if (osc_data->is_queried &&
- ((osc_data->query_result & ctrlset) != ctrlset))
- return AE_SUPPORT;
+ ((osc_data->query_result & ctrlset) != ctrlset)) {
+ status = AE_SUPPORT;
+ goto out;
+ }
control_set = osc_data->control_set | ctrlset;
osc_args.capbuf[OSC_QUERY_TYPE] = 0;
@@ -211,7 +222,8 @@
status = acpi_run_osc(handle, &osc_args);
if (ACPI_SUCCESS(status))
osc_data->control_set = control_set;
-
+out:
+ mutex_unlock(&pci_acpi_lock);
return status;
}
EXPORT_SYMBOL(pci_osc_control_set);