Re: [PATCH v3 1/4] usb: typec: ucsi: Fix null pointer dereference in trace

[Benson Leung]

Hi Jameson,

On Fri, May 03, 2024 at 12:39:17AM +0000, Jameson Thies wrote:
> From: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> 
> ucsi_register_altmode checks IS_ERR on returned pointer and treats
> NULL as valid. When CONFIG_TYPEC_DP_ALTMODE is not enabled
> ucsi_register_displayport returns NULL which causese a NULL pointer
> dereference in trace. Rather than return NULL, call
> typec_port_register_altmode to register DisplayPort alternate mode
> as a non-controllable mode when CONFIG_TYPEC_DP_ALTMODE is not enabled.
> 
> Reviewed-by: Jameson Thies <jthies@xxxxxxxxxx>
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>

Reviewed-by: Benson Leung <bleung@xxxxxxxxxxxx>

> ---
> Changes in V3:
> - Returns typec_port_register_altmode call from
> ucsi_register_displayport when CONFIG_TYPEC_DP_ALTMODE is not enabled.
> 
> Changes in V2:
> - Checks for error response from ucsi_register_displayport when
> registering DisplayPort alternate mode.
> 
>  drivers/usb/typec/ucsi/ucsi.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
> index c4d103db9d0f8..f66224a270bc6 100644
> --- a/drivers/usb/typec/ucsi/ucsi.h
> +++ b/drivers/usb/typec/ucsi/ucsi.h
> @@ -496,7 +496,7 @@ ucsi_register_displayport(struct ucsi_connector *con,
>  			  bool override, int offset,
>  			  struct typec_altmode_desc *desc)
>  {
> -	return NULL;
> +	return typec_port_register_altmode(con->port, desc);
>  }
>  
>  static inline void
> -- 
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>

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