Re: [PATCH v3 2/2] misc: amd-sbi: Address copy_to/from_user() warning reported in smatch

[Greg KH]

On Tue, Jul 01, 2025 at 05:40:41AM +0000, Akshay Gupta wrote:
> Smatch warnings are reported for below commit,
> 
> Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
> from Apr 28, 2025 (linux-next), leads to the following Smatch static
> checker warning:
> 
> drivers/misc/amd-sbi/rmi-core.c:376 apml_rmi_reg_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:394 apml_mailbox_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:411 apml_cpuid_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:428 apml_mcamsr_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> 
> copy_to/from_user() returns number of bytes, not copied.
> In case data not copied, return "-EFAULT".
> Additionally, fixes the "-EPROTOTYPE" error return as intended.
> 
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
> Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@xxxxxxx>
> Signed-off-by: Akshay Gupta <akshay.gupta@xxxxxxx>
> ---
> Changes from v2:
>  - Update commit message to add, "fix the -EPROTOTYPE error return".
> 
> Changes from v1:
>  - Split patch as per Greg's suggestion
> 
>  drivers/misc/amd-sbi/rmi-core.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
> index 3570f3b269a9..9048517c088c 100644
> --- a/drivers/misc/amd-sbi/rmi-core.c
> +++ b/drivers/misc/amd-sbi/rmi-core.c
> @@ -372,7 +372,8 @@ static int apml_rmi_reg_xfer(struct sbrmi_data *data,
>  	mutex_unlock(&data->lock);
>  
>  	if (msg.rflag && !ret)
> -		return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg));
> +		if (copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)))
> +			return -EFAULT;
>  	return ret;

What commit id does this change fix?

thanks,

greg k-h