From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki K Poulose Subject: Re: [PATCH 01/20] coresight: Fix memory leak in coresight_register Date: Wed, 6 Jun 2018 11:16:26 +0100 Message-ID: <16154816-2760-8582-23f1-da607b344db6@arm.com> References: <1528235011-30691-1-git-send-email-suzuki.poulose@arm.com> <1528235011-30691-2-git-send-email-suzuki.poulose@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Arvind Yadav , linux-arm-kernel@lists.infradead.org Cc: mathieu.poirier@linaro.org, robh@kernel.org, frowand.list@gmail.com, mark.rutland@arm.com, sudeep.holla@arm.com, arm@kernel.org, linux-kernel@vger.kernel.org, matt.sealey@arm.com, john.horley@arm.com, charles.garcia-tobin@arm.com, coresight@lists.linaro.org, devicetree@vger.kernel.org, mike.leach@linaro.org List-Id: devicetree@vger.kernel.org On 06/06/2018 07:44 AM, Arvind Yadav wrote: > Hi Suzuki, > > > On Wednesday 06 June 2018 03:13 AM, Suzuki K Poulose wrote: >> commit 6403587a930c ("coresight: use put_device() instead of kfree()") >> introduced a memory leak where, if we fail to register the device >> for coresight_device, we don't free the "coresight_device" object, >> which was allocated via kzalloc(). Fix this by jumping to the >> appropriate error path. > 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. If you will see the coresight_device_release. There > we are releasing all allocated memory. Still if you call kfree() again > then it'll be redundancy. You're right. I think it would be good to have a comment explaining this to prevent this fix popping up in the future :-). I will add it Thanks Suzuki