Re: [PATCH] vt: keyboard, fix uninitialized variables warning

[Greg KH]

On Wed, Mar 03, 2021 at 12:59:32PM +0800, Li Wang wrote:
> drivers/tty/vt/keyboard.c: In function 'vt_do_kdgkb_ioctl':
> drivers/tty/vt/keyboard.c: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   return ret;
>          ^~~
> kernel-source/drivers/tty/vt/keyboard.c: warning: 'kbs' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   kfree(kbs);
>   ^~~~~~~~~~
> 
> Signed-off-by: Li Wang <li.wang@xxxxxxxxxxxxx>
> ---
>  drivers/tty/vt/keyboard.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
> index 7763862..3e73d55 100644
> --- a/drivers/tty/vt/keyboard.c
> +++ b/drivers/tty/vt/keyboard.c
> @@ -2049,8 +2049,8 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
>  {
>  	unsigned char kb_func;
>  	unsigned long flags;
> -	char *kbs;
> -	int ret;
> +	char *kbs = NULL;
> +	int ret = -EINVAL;
>  
>  	if (get_user(kb_func, &user_kdgkb->kb_func))
>  		return -EFAULT;

What compiler is providing these "warnings"?

Turns out it is impossible to hit, so this isn't actually fixing
anything...

thanks,

greg k-h