From f18a9531f6da9aba2920a3a5f166dba5a20592a0 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Mon, 7 Mar 2016 17:04:45 +0200 Subject: [PATCH] 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 Reviewed-by: Laurent Fert --- drivers/hwtracing/intel_th/core.c | 12 ++++++++++-- drivers/hwtracing/intel_th/intel_th.h | 3 +++ 2 files changed, 13 insertions(+), 2 deletions(-) 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 DEVICE_ATTR_RO(port); 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 int intel_th_output_activate(struct intel_th_device *thdev) 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 @@ struct intel_th_driver { #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) { -- 2.7.4