From: Jon Hunter <jonathanh@nvidia.com>
To: Gen Zhang <blackgod016574@gmail.com>, <lgirdwood@gmail.com>,
<perex@perex.cz>
Cc: <alsa-devel@alsa-project.org>, <linux-tegra@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tegra_wm9712: Fix a memory leaking bug in tegra_wm9712_driver_probe()
Date: Fri, 24 May 2019 09:33:13 +0100 [thread overview]
Message-ID: <b2d43dfe-17e5-a975-435b-49f2aa2ad550@nvidia.com> (raw)
In-Reply-To: <20190524005014.GA2289@zhanggen-UX430UQ>
On 24/05/2019 01:50, Gen Zhang wrote:
> In tegra_wm9712_driver_probe(), 'machine->codec' is allocated by
> platform_device_alloc(). When it is NULL, function returns ENOMEM.
> However, 'machine' is allocated by devm_kzalloc() before this site.
> Thus we should free 'machine' before function ends to prevent memory
> leaking.
Memory allocated by devm_xxx() is automatically freed on failure so this
is not correct.
> Further, we should free 'machine->util_data', 'machine->codec' and
> 'machine' before this function normally ends to prevent memory leaking.
This is also incorrect. Why would we free all resources after
successfully initialising the driver?
> Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> ---
> diff --git a/sound/soc/tegra/tegra_wm9712.c b/sound/soc/tegra/tegra_wm9712.c
> index 864a334..295c41d 100644
> --- a/sound/soc/tegra/tegra_wm9712.c
> +++ b/sound/soc/tegra/tegra_wm9712.c
> @@ -86,7 +86,8 @@ static int tegra_wm9712_driver_probe(struct platform_device *pdev)
> machine->codec = platform_device_alloc("wm9712-codec", -1);
> if (!machine->codec) {
> dev_err(&pdev->dev, "Can't allocate wm9712 platform device\n");
> - return -ENOMEM;
> + ret = -ENOMEM;
> + goto codec_free;
> }
>
> ret = platform_device_add(machine->codec);
> @@ -127,6 +128,10 @@ static int tegra_wm9712_driver_probe(struct platform_device *pdev)
> goto asoc_utils_fini;
> }
>
> + tegra_asoc_utils_fini(&machine->util_data);
> + platform_device_del(machine->codec);
> + platform_device_put(machine->codec);
> + devm_kfree(&pdev->dev, machine);
> return 0;
As stated above, this is incorrect.
Did you actually test this? I think you would find this would break the
driver.
Jon
--
nvpublic
next prev parent reply other threads:[~2019-05-24 8:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 0:50 [PATCH] tegra_wm9712: Fix a memory leaking bug in tegra_wm9712_driver_probe() Gen Zhang
2019-05-24 8:33 ` Jon Hunter [this message]
2019-05-24 14:33 ` Gen Zhang
2019-05-24 14:47 ` Jon Hunter
2019-05-24 15:00 ` Gen Zhang
2019-05-24 15:36 ` Jon Hunter
2019-05-24 15:42 ` Gen Zhang
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