Re: [PATCH] [v2] media: platform: amd: avoid -Wformat-security warning

[David Laight]

On Fri,  8 May 2026 14:43:49 +0200
Arnd Bergmann <arnd@xxxxxxxxxx> wrote:

> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> The newly added kthread_run() call passes a string variable as an sprintf()
> style format, which gcc warns about when -Wformat-security is enabled:
> 
> drivers/media/platform/amd/isp4/isp4_subdev.c: In function 'isp4sd_start_resp_proc_threads':
> include/linux/kthread.h:71:16: error: format not a string literal and no format arguments [-Werror=format-security]
>    71 |         struct task_struct *__k                                            \
>       |                ^~~~~~~~~~~
> drivers/media/platform/amd/isp4/isp4_subdev.c:596:38: note: in expansion of macro 'kthread_run'
>   596 |                 thread_ctx->thread = kthread_run(isp4sd_fw_resp_thread,
>       |                                      ^~~~~~~~~~~
> 
> Use an indirect "%s" format to do this safely, avoiding the warning.
> 
> Fixes: 4e5e7a7ddb4a ("media: platform: amd: isp4 subdev and firmware loading handling added")
> Tested-by: Bin Du <Bin.Du@xxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v2: avoid overly long line
> ---
>  drivers/media/platform/amd/isp4/isp4_subdev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/platform/amd/isp4/isp4_subdev.c b/drivers/media/platform/amd/isp4/isp4_subdev.c
> index 48deea79ce6c..427e9ba910bb 100644
> --- a/drivers/media/platform/amd/isp4/isp4_subdev.c
> +++ b/drivers/media/platform/amd/isp4/isp4_subdev.c
> @@ -595,6 +595,7 @@ static int isp4sd_start_resp_proc_threads(struct isp4_subdev *isp_subdev)
>  
>  		thread_ctx->thread = kthread_run(isp4sd_fw_resp_thread,
>  						 &isp_subdev->isp_resp_para[i],
> +						 "%s",
>  						 isp4sd_thread_name[i]);

I don't think the line break is needed.
I always prefer a line break between the format and arguments when the whole
lot doesn't fit on one line; but here it fits.

-- David



>  		if (IS_ERR(thread_ctx->thread)) {
>  			dev_err(dev, "create thread [%d] fail\n", i);