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References: <20201011212135.GD8773@valentin-vidic.from.hr> <20201011220329.13038-1-vvidic@valentin-vidic.from.hr>
In-Reply-To: <20201011220329.13038-1-vvidic@valentin-vidic.from.hr>
From:   Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date:   Sun, 11 Oct 2020 18:53:31 -0400
Message-ID: <CA+FuTSfFcyVPd3Tr=wFSfSFBojpXPMZGmPvS0m+iM4TiRpsM5w@mail.gmail.com>
Subject: Re: [PATCH v2] net: korina: fix kfree of rx/tx descriptor array
To:     Valentin Vidic <vvidic@valentin-vidic.from.hr>
Cc:     Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Philip Rischel <rischelp@idt.com>,
        Florian Fainelli <florian@openwrt.org>,
        Roman Yeryomin <roman@advem.lv>,
        Jakub Kicinski <kuba@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@kernel.org>,
        Martin Habets <mhabets@solarflare.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Network Development <netdev@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Sun, Oct 11, 2020 at 6:04 PM Valentin Vidic
<vvidic@valentin-vidic.from.hr> wrote:
>
> kmalloc returns KSEG0 addresses so convert back from KSEG1
> in kfree. Also make sure array is freed when the driver is
> unloaded from the kernel.
>
> Fixes: ef11291bcd5f ("Add support the Korina (IDT RC32434) Ethernet MAC")
> Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>

Ah, this a MIPS architecture feature, both KSEGs mapping the same
region, just cachable vs non-cachable.

Acked-by: Willem de Bruijn <willemb@google.com>


> ---
>  v2: convert kfree address back to KSEG0
>
>  drivers/net/ethernet/korina.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/korina.c b/drivers/net/ethernet/korina.c
> index 03e034918d14..af441d699a57 100644
> --- a/drivers/net/ethernet/korina.c
> +++ b/drivers/net/ethernet/korina.c
> @@ -1113,7 +1113,7 @@ static int korina_probe(struct platform_device *pdev)
>         return rc;
>
>  probe_err_register:
> -       kfree(lp->td_ring);
> +       kfree(KSEG0ADDR(lp->td_ring));
>  probe_err_td_ring:
>         iounmap(lp->tx_dma_regs);
>  probe_err_dma_tx:
> @@ -1133,6 +1133,7 @@ static int korina_remove(struct platform_device *pdev)
>         iounmap(lp->eth_regs);
>         iounmap(lp->rx_dma_regs);
>         iounmap(lp->tx_dma_regs);
> +       kfree(KSEG0ADDR(lp->td_ring));
>
>         unregister_netdev(bif->dev);
>         free_netdev(bif->dev);
> --
> 2.20.1
>