linux-kernel - Re: [PATCH 01/20] coresight: Fix memory leak in coresight

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 6 Jun 2018 11:16:26 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Arvind Yadav <arvind.yadav.cs@...il.com>,
        linux-arm-kernel@...ts.infradead.org
Cc:     mathieu.poirier@...aro.org, robh@...nel.org,
        frowand.list@...il.com, mark.rutland@....com, sudeep.holla@....com,
        arm@...nel.org, linux-kernel@...r.kernel.org, matt.sealey@....com,
        john.horley@....com, charles.garcia-tobin@....com,
        coresight@...ts.linaro.org, devicetree@...r.kernel.org,
        mike.leach@...aro.org
Subject: Re: [PATCH 01/20] coresight: Fix memory leak in coresight_register

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