Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v1] media: camss: vfe: Don't use vfe->base before it's
 assigned
To:     Robert Foss <robert.foss@linaro.org>, todor.too@gmail.com,
        agross@kernel.org, bjorn.andersson@linaro.org, mchehab@kernel.org,
        hverkuil-cisco@xs4all.nl, linux-media@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        Hans Verkuil <hverkuil@xs4all.nl>
Cc:     Linux Kernel Functional Testing <lkft@linaro.org>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <0b694e24-5cc8-4944-d3a2-115306ae7b89@samsung.com>
Date:   Wed, 11 Aug 2021 09:48:32 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0)
        Gecko/20100101 Thunderbird/78.13.0
MIME-Version: 1.0
In-Reply-To: <20210810103336.114077-1-robert.foss@linaro.org>
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <20210810103336.114077-1-robert.foss@linaro.org>
        <CGME20210811074838eucas1p2a0e8625af27c10209d9bcfc732254ae7@eucas1p2.samsung.com>
Precedence: bulk

On 10.08.2021 12:33, Robert Foss wrote:
> vfe->ops->hw_version(vfe) being called before vfe->base has been assigned
> is incorrect and causes crashes.
>
> Fixes: b10b5334528a9 ("media: camss: vfe: Don't read hardware version needlessly")
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Signed-off-by: Robert Foss <robert.foss@linaro.org>

With this patch applied on top of linux next-20210810 instead of the 
NULL pointer dereference I get following error on DragonBoard410c while 
loading kernel modules:

[   18.480608] qcom-venus 1d00000.video-codec: Adding to iommu group 1
[   18.536167] qcom-camss 1b0ac00.camss: Adding to iommu group 2
[   18.600373] Internal error: synchronous external abort: 96000010 [#1] 
PREEMPT SMP

> ---
>   drivers/media/platform/qcom/camss/camss-vfe.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/qcom/camss/camss-vfe.c b/drivers/media/platform/qcom/camss/camss-vfe.c
> index 6b2f33fc9be22..1c8d2f0f81207 100644
> --- a/drivers/media/platform/qcom/camss/camss-vfe.c
> +++ b/drivers/media/platform/qcom/camss/camss-vfe.c
> @@ -1299,7 +1299,6 @@ int msm_vfe_subdev_init(struct camss *camss, struct vfe_device *vfe,
>   		return -EINVAL;
>   	}
>   	vfe->ops->subdev_init(dev, vfe);
> -	vfe->ops->hw_version(vfe);
>   
>   	/* Memory */
>   
> @@ -1309,6 +1308,8 @@ int msm_vfe_subdev_init(struct camss *camss, struct vfe_device *vfe,
>   		return PTR_ERR(vfe->base);
>   	}
>   
> +	vfe->ops->hw_version(vfe);
> +
>   	/* Interrupt */
>   
>   	r = platform_get_resource_byname(pdev, IORESOURCE_IRQ,

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland