intel_th: Fix activating a subdevice without a driver
If output subdevice driver is not loaded, activating it will try to
call its ->activate method and crash. Fix this by explicitly checking
for the driver.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
index db06919..2033947 100644
--- a/drivers/hwtracing/intel_th/core.c
+++ b/drivers/hwtracing/intel_th/core.c
@@ -183,7 +183,11 @@
static int intel_th_output_activate(struct intel_th_device *thdev)
{
- struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+ struct intel_th_driver *thdrv =
+ to_intel_th_driver_or_null(thdev->dev.driver);
+
+ if (!thdrv)
+ return -ENODEV;
if (thdrv->activate)
return thdrv->activate(thdev);
@@ -195,7 +199,11 @@
static void intel_th_output_deactivate(struct intel_th_device *thdev)
{
- struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+ struct intel_th_driver *thdrv =
+ to_intel_th_driver_or_null(thdev->dev.driver);
+
+ if (!thdrv)
+ return;
if (thdrv->deactivate)
thdrv->deactivate(thdev);
diff --git a/drivers/hwtracing/intel_th/intel_th.h b/drivers/hwtracing/intel_th/intel_th.h
index 15ebd48..0df22e3 100644
--- a/drivers/hwtracing/intel_th/intel_th.h
+++ b/drivers/hwtracing/intel_th/intel_th.h
@@ -151,6 +151,9 @@
#define to_intel_th_driver(_d) \
container_of((_d), struct intel_th_driver, driver)
+#define to_intel_th_driver_or_null(_d) \
+ ((_d) ? to_intel_th_driver(_d) : NULL)
+
static inline struct intel_th_device *
to_intel_th_hub(struct intel_th_device *thdev)
{