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Date:   Sun, 20 Nov 2022 12:49:01 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To:     Ziyang Xuan <william.xuanziyang@huawei.com>
Cc:     nbd@nbd.name, john@phrozen.org, sean.wang@mediatek.com,
        Mark-MC.Lee@mediatek.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, matthias.bgg@gmail.com,
        linux@armlinux.org.uk, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        lorenzo@kernel.org
Subject: Re: [PATCH net] net: ethernet: mtk_eth_soc: fix potential memory
 leak in mtk_rx_alloc()
Message-ID: <Y3oULSsTwbDY2Bvv@lore-desk>
References: <20221120035405.1464341-1-william.xuanziyang@huawei.com>
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> When fail to dma_map_single() in mtk_rx_alloc(), it returns directly.
> But the memory allocated for local variable data is not freed, and
> local variabel data has not been attached to ring->data[i] yet, so the
> memory allocated for local variable data will not be freed outside
> mtk_rx_alloc() too. Thus memory leak would occur in this scenario.
>=20
> Add skb_free_frag(data) when dma_map_single() failed.
>=20
> Fixes: 23233e577ef9 ("net: ethernet: mtk_eth_soc: rely on page_pool for s=
ingle page buffers")
> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Acked-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

>=20
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/et=
hernet/mediatek/mtk_eth_soc.c
> index 7cd381530aa4..bc47ef1e4dd5 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -2378,8 +2378,10 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int r=
ing_no, int rx_flag)
>  				data + NET_SKB_PAD + eth->ip_align,
>  				ring->buf_size, DMA_FROM_DEVICE);
>  			if (unlikely(dma_mapping_error(eth->dma_dev,
> -						       dma_addr)))
> +						       dma_addr))) {
> +				skb_free_frag(data);
>  				return -ENOMEM;
> +			}
>  		}
>  		rxd->rxd1 =3D (unsigned int)dma_addr;
>  		ring->data[i] =3D data;
> --=20
> 2.25.1
>=20

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