On Tuesday 27 March 2018 03:16 AM, Mathieu Poirier wrote:
drivers/hwtracing/coresight/coresight.c On 18 March 2018 at 01:38, Arvind Yadav <arvind.yadav...@gmail.com> wrote:Never directly free @dev after calling device_register(), even if it returned an error. Always use put_device() to give up the reference initialized. Signed-off-by: Arvind Yadav <arvind.yadav...@gmail.com> --- drivers/hwtracing/coresight/coresight.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 389c4ba..132dfbc 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -1026,8 +1026,10 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) dev_set_name(&csdev->dev, "%s", desc->pdata->name); ret = device_register(&csdev->dev); - if (ret) - goto err_device_register; + if (ret) { + put_device(&csdev->dev); + goto err_kzalloc_csdev; + } mutex_lock(&coresight_mutex); @@ -1038,8 +1040,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) return csdev; -err_device_register: - kfree(conns);Apologies for the late reply, I was travelling. I suggest to simply replace kfree() with put_device() in order to concentrate the error handling code in the same area and make sure that memory allocated for @conns and @refcnts is freed. Thanks, Mathieu
If you will see the comment for device_register(drivers/base/core.c) there is mentioned that 'NOTE: _Never_ directly free @dev after calling this function, even if it returned an error! Always use put_device() to give up the reference initialized in this function instead. Here put_device() will decrement the last reference and then free the memory by calling dev->release. Internally put_device() -> kobject_put() -> kobject_cleanup() which is responsible to call 'dev -> release' and also free other kobject resources. we should always avoid kfree() if device_register() returned an error. Otherwise it'll not do clean up of other kobject resources. ~arvind
err_kzalloc_conns: kfree(refcnts); err_kzalloc_refcnts: -- 2.7.4
