From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932902AbcDTKrr (ORCPT ); Wed, 20 Apr 2016 06:47:47 -0400 Received: from mga14.intel.com ([192.55.52.115]:55152 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754708AbcDTKob (ORCPT ); Wed, 20 Apr 2016 06:44:31 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,509,1455004800"; d="scan'208";a="949073077" From: Alexander Shishkin To: Greg KH Cc: Mathieu Poirier , Chunyan Zhang , laurent.fert@intel.com, yann.fouassier@intel.com, linux-kernel@vger.kernel.org, Alexander Shishkin Subject: [QUEUED v20160420 14/19] intel_th: Fix activating a subdevice without a driver Date: Wed, 20 Apr 2016 13:43:27 +0300 Message-Id: <1461149012-26954-15-git-send-email-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1461149012-26954-1-git-send-email-alexander.shishkin@linux.intel.com> References: <1461149012-26954-1-git-send-email-alexander.shishkin@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 db0691929a..20339470c2 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 15ebd48a29..0df22e3067 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) { -- 2.8.0.rc3