Re: [PATCH] soc: aspeed: Add NULL pointer check in aspeed_lpc_enable_snoop()

[Andrew Jeffery <andrew@codeconstruct.com.au>]

Hi Chenyuan,

On Wed, 2025-02-12 at 15:25 -0600, Chenyuan Yang wrote:
> lpc_snoop->chan[channel].miscdev.name could be NULL, thus,
> a pointer check is added to prevent potential NULL pointer
> dereference.
> This is similar to the fix in commit 3027e7b15b02
> ("ice: Fix some null pointer dereference issues in ice_ptp.c").
> 
> This issue is found by our static analysis tool.
> 
> Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
> ---
>  drivers/soc/aspeed/aspeed-lpc-snoop.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c
> b/drivers/soc/aspeed/aspeed-lpc-snoop.c
> index 9ab5ba9cf1d6..376b3a910797 100644
> --- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
> +++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
> @@ -200,6 +200,8 @@ static int aspeed_lpc_enable_snoop(struct
> aspeed_lpc_snoop *lpc_snoop,
>         lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
>         lpc_snoop->chan[channel].miscdev.name =
>                 devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME,
> channel);
> +       if (!lpc_snoop->chan[channel].miscdev.name)
> +               return -ENOMEM;

This introduces yet another place where the driver leaks resources in
an error path (in this case, the channel kfifo). The misc device also
gets leaked later on. It would be nice to address those first so that
handling this error can take the appropriate cleanup path.

Andrew