Re: [PATCH v1] media: camss: vfe: Don't use vfe->base before it's assigned

[Marek Szyprowski]

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@xxxxxxxxxx>
> Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>

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