Re: [PATCH v4 2/2] media: amphion: prevent unbind while video instances are open

["Ming Qian(OSS)" <ming.qian@oss.nxp.com>]

On 9/26/2026 3:17 AM, Myeonghun Pak wrote:
> An open video instance holds a plain pointer to its devm-allocated core.
> Unbinding the core or its parent through sysfs can release that memory
> while the instance remains open. A later ioctl or close then uses the
> stale pointer.
> 
> The video file operations pin the module, but sysfs unbind bypasses that
> protection. Suppress manual bind and unbind for both platform drivers,
> and warn if core removal ever encounters a live instance.
> 
> Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
> Cc: stable@vger.kernel.org
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

Reviewed-by: Ming Qian <ming.qian@oss.nxp.com>

> ---
>   drivers/media/platform/amphion/vpu_core.c | 3 +++
>   drivers/media/platform/amphion/vpu_drv.c  | 1 +
>   2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/media/platform/amphion/vpu_core.c b/drivers/media/platform/amphion/vpu_core.c
> index a0c58ec97a42..2e8e08e05de7 100644
> --- a/drivers/media/platform/amphion/vpu_core.c
> +++ b/drivers/media/platform/amphion/vpu_core.c
> @@ -696,6 +696,8 @@ static void vpu_core_remove(struct platform_device *pdev)
>   	struct vpu_core *core = platform_get_drvdata(pdev);
>   	int ret;
>   
> +	WARN_ON(!list_empty(&core->instances));
> +
>   	vpu_core_remove_dbgfs_file(core);
>   	ret = pm_runtime_resume_and_get(dev);
>   	WARN_ON(ret < 0);
> @@ -846,6 +848,7 @@ static struct platform_driver amphion_vpu_core_driver = {
>   	.remove = vpu_core_remove,
>   	.driver = {
>   		.name = "amphion-vpu-core",
> +		.suppress_bind_attrs = true,
>   		.of_match_table = vpu_core_dt_match,
>   		.pm = &vpu_core_pm_ops,
>   	},
> diff --git a/drivers/media/platform/amphion/vpu_drv.c b/drivers/media/platform/amphion/vpu_drv.c
> index 2cca61f41bea..9c6f32c5eae9 100644
> --- a/drivers/media/platform/amphion/vpu_drv.c
> +++ b/drivers/media/platform/amphion/vpu_drv.c
> @@ -205,6 +205,7 @@ static struct platform_driver amphion_vpu_driver = {
>   	.remove = vpu_remove,
>   	.driver = {
>   		.name = "amphion-vpu",
> +		.suppress_bind_attrs = true,
>   		.of_match_table = vpu_dt_match,
>   	},
>   };