linux-kernel - Re: [alsa-devel] [PATCH v2] ASoC: Intel: Skylake: prevent memory leak in snd_skl_parse

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Message-ID: <3428d5e2-3246-7e1c-cb4d-59351193e4de@linux.intel.com>
Date:   Fri, 27 Sep 2019 17:25:41 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Cezary Rojewski <cezary.rojewski@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jie Yang <yang.jie@...ux.intel.com>,
        ALSA Development Mailing List <alsa-devel@...a-project.org>,
        Navid Emamdoost <navid.emamdoost@...il.com>,
        Takashi Iwai <tiwai@...e.com>,
        Liam Girdwood <liam.r.girdwood@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        Stephen McCamant <smccaman@....edu>, Kangjie Lu <kjlu@....edu>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Enrico Weigelt <info@...ux.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Navid Emamdoost <emamd001@....edu>
Subject: Re: [alsa-devel] [PATCH v2] ASoC: Intel: Skylake: prevent memory leak
 in snd_skl_parse_uuids

On 9/27/19 3:39 PM, Andy Shevchenko wrote:
> On Fri, Sep 27, 2019 at 7:39 PM Pierre-Louis Bossart
> <pierre-louis.bossart@...ux.intel.com> wrote:
>>> The problem with solution #1 is freeing orphaned pointer. It will work,
>>> but it's simple is not okay from object life time prospective.
>>
>> ?? I don't get your point at all Andy.
>> Two allocations happens in a loop and if the second fails, you free the
>> first and then jump to free everything allocated in the previous
>> iterations. what am I missing?
> 
> Two things:
>   - one allocation is done with kzalloc(), while the other one with
> devm_kcalloc()
>   - due to above the ordering of resources is reversed

Ah yes, I see your point now, sorry for being thick.
Indeed it'd make sense to use devm_ for both allocations, but then the 
kfree needs to be removed in the error handling.