Re: [PATCH v2] media: verisilicon: Fix kernel panic due to __initconst misuse

[Marco Felsch]

On 26-03-05, ming.qian@xxxxxxxxxxx wrote:
> From: Ming Qian <ming.qian@xxxxxxxxxxx>
> 
> Fix a kernel panic when probing the driver as a module:
> 
>   Unable to handle kernel paging request at virtual address
>   ffffd9c18eb05000
>   of_find_matching_node_and_match+0x5c/0x1a0
>   hantro_probe+0x2f4/0x7d0 [hantro_vpu]
> 
> The imx8mq_vpu_shared_resources array is referenced by variant
> structures through their shared_devices field. When built as a
> module, __initconst causes this data to be freed after module
> init, but it's later accessed during probe, causing a page fault.
> 
> The imx8mq_vpu_shared_resources is referenced from non-init code,
> so keeping __initconst or __initconst_or_module here is wrong.
> 
> Drop the __initconst annotation and let it live in the normal .rodata
> section.
> 
> Fixes: e0203ddf9af7 ("media: verisilicon: Avoid G2 bus error while decoding H.264 and HEVC")
> Reported-by: Franz Schnyder <franz.schnyder@xxxxxxxxxxx>
> Closes: https://lore.kernel.org/all/n3qmcb62tepxltoskpf7ws6yiirc2so62ia23b42rj3wlmpl67@rvkbuirx7kkp/
> Suggested-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>

This fix was suggested by Krzysztof :)

> Signed-off-by: Ming Qian <ming.qian@xxxxxxxxxxx>
> ---
> v2
> - Remove __initconst
> - Add missing Reported-by tag
> - Add missing Suggested-by tag
> - Remove comments of sentinel to pass checkpatch.pl
> 
>  drivers/media/platform/verisilicon/imx8m_vpu_hw.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
> index 6f8e43b7f157..6fbe3c581032 100644
> --- a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
> +++ b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
> @@ -343,10 +343,10 @@ const struct hantro_variant imx8mq_vpu_variant = {
>  	.num_regs = ARRAY_SIZE(imx8mq_reg_names)
>  };
>  
> -static const struct of_device_id imx8mq_vpu_shared_resources[] __initconst = {
> +static const struct of_device_id imx8mq_vpu_shared_resources[] = {
>  	{ .compatible = "nxp,imx8mq-vpu-g1", },
>  	{ .compatible = "nxp,imx8mq-vpu-g2", },
> -	{ /* sentinel */ }
> +	{}

Unnecessary change.

With both fixed:

Reviewed-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>


>  };
>  
>  const struct hantro_variant imx8mq_vpu_g1_variant = {
> -- 
> 2.52.0
> 
> 

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