Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230629134306.95823-1-jonas.gorski@gmail.com>
In-Reply-To: <20230629134306.95823-1-jonas.gorski@gmail.com>
From:   Kamal Dasu <kamal.dasu@broadcom.com>
Date:   Thu, 29 Jun 2023 11:06:44 -0400
Message-ID: <CAKekbeuMjUPpzfgKrxgZzFpiQ4FbeYtBtbrzkWKeBy4u2Symhg@mail.gmail.com>
Subject: Re: [PATCH] spi: bcm-qspi: return error if neither hif_mspi nor mspi
 is available
To:     Jonas Gorski <jonas.gorski@gmail.com>
Cc:     Kamal Dasu <kdasu.kdev@gmail.com>,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@broadcom.com>,
        Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256;
        boundary="0000000000009ed7c605ff460e7f"
Precedence: bulk

--0000000000009ed7c605ff460e7f
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Thu, Jun 29, 2023 at 9:43=E2=80=AFAM Jonas Gorski <jonas.gorski@gmail.co=
m> wrote:
>
> If neither a "hif_mspi" nor "mspi" resource is present, the driver will
> just early exit in probe but still return success. Apart from not doing
> anything meaningful, this would then also lead to a null pointer access
> on removal, as platform_get_drvdata() would return NULL, which it would
> then try to dereferce when trying to unregister the spi master.
>
> Fix this by unconditionally calling devm_ioremap_resource(), as it can
> handle a NULL res and will then return a viable ERR_PTR() if we get one.
>
> The "return 0;" was previously a "goto qspi_resource_err;" where then
> ret was returned, but since ret was still initialized to 0 at this place
> this was a valid conversion in 63c5395bb7a9 ("spi: bcm-qspi: Fix
> use-after-free on unbind"). The issue was not introduced by this commit,
> only made more obvious.
>
> Fixes: fa236a7ef240 ("spi: bcm-qspi: Add Broadcom MSPI driver")
> Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
> ---
> Found by looking a the driver while comparing it to its bindings.
>
> Only build tested, not runtested.
>
>  drivers/spi/spi-bcm-qspi.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
> index 6b46a3b67c41..d91dfbe47aa5 100644
> --- a/drivers/spi/spi-bcm-qspi.c
> +++ b/drivers/spi/spi-bcm-qspi.c
> @@ -1543,13 +1543,9 @@ int bcm_qspi_probe(struct platform_device *pdev,
>                 res =3D platform_get_resource_byname(pdev, IORESOURCE_MEM=
,
>                                                    "mspi");
>
> -       if (res) {
> -               qspi->base[MSPI]  =3D devm_ioremap_resource(dev, res);
> -               if (IS_ERR(qspi->base[MSPI]))
> -                       return PTR_ERR(qspi->base[MSPI]);
> -       } else {
> -               return 0;
> -       }

I would rather just do this in the else case

} else {
 -              return 0;
 +             return -ENODEV;
}

 The change below does not check the return of
platform_get_resource_byname() in my opinion rather relies on
devm_ioremap_resource() doing the right thing.

> +       qspi->base[MSPI]  =3D devm_ioremap_resource(dev, res);
> +       if (IS_ERR(qspi->base[MSPI]))
> +               return PTR_ERR(qspi->base[MSPI]);
>
>         res =3D platform_get_resource_byname(pdev, IORESOURCE_MEM, "bspi"=
);
>         if (res) {
> --
> 2.34.1
>

--0000000000009ed7c605ff460e7f
Content-Type: application/pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
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--0000000000009ed7c605ff460e7f--