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From:   <Tudor.Ambarus@microchip.com>
To:     <pavel@ucw.cz>, <linux-kernel@vger.kernel.org>,
        <dmaengine@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <dan.j.williams@intel.com>,
        <vkoul@kernel.org>, <Ludovic.Desroches@microchip.com>,
        <stable@vger.kernel.org>, <greg@kroah.com>
Subject: Re: [PATCH 4.19] dmaengine: at_hdmac: Fix memory leak
Thread-Topic: [PATCH 4.19] dmaengine: at_hdmac: Fix memory leak
Thread-Index: AQHWkYFbVNgbQZmRd0SqW2sKLrUKIA==
Date:   Wed, 23 Sep 2020 08:13:02 +0000
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Hi, Pavel,

On 9/20/20 11:28 AM, Pavel Machek wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know th=
e content is safe
>=20
> This fixes memory leak in at_hdmac. Mainline does not have the same
> problem.
>=20
> Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
>=20
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index 86427f6ba78c..0847b2055857 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -1714,8 +1714,10 @@ static struct dma_chan *at_dma_xlate(struct of_pha=
ndle_args *dma_spec,
>         atslave->dma_dev =3D &dmac_pdev->dev;
>=20
>         chan =3D dma_request_channel(mask, at_dma_filter, atslave);
> -       if (!chan)
> +       if (!chan) {
> +               kfree(atslave);
>                 return NULL;
> +       }

Thanks for submitting this to stable. While the fix is good, you can instea=
d
cherry-pick the commit that hit upstream. In order to do that cleanly on to=
p
of v4.19.145, you have to pick two other fixes:

commit a6e7f19c9100 ("dmaengine: at_hdmac: Substitute kzalloc with kmalloc"=
)
commit 3832b78b3ec2 ("dmaengine: at_hdmac: add missing put_device() call in=
 at_dma_xlate()")
commit a6e7f19c9100 ("dmaengine: at_hdmac: Substitute kzalloc with kmalloc"=
)

There are also some locking/deadlock fixes in mainline for this driver,
depending on the time you can allocate for this, the list of patches can in=
crease.
I should have Cc'ed stable@vger.kernel.org in the first place, my bad.

Also it may worth to read the rules for submitting to stable at:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

Cheers,
ta