Re: [PATCH net v1] iavf: add missing PTP adjustment callbacks

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 28/08/2026 02:58, Xuanqiang Luo wrote:
> From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
> 
> The PTP hardware clock documentation requires drivers to implement all
> callbacks and return -EOPNOTSUPP for unsupported features.
> 
> The iavf driver registers a PHC without adjtime or adjfine callbacks.
> A userspace clock_adjtime(2) request reaches ptp_clock_adjtime(), where
> ADJ_SETOFFSET calls adjtime and ADJ_FREQUENCY calls adjfine. The missing
> callbacks can therefore cause a NULL dereference.
> 
> Provide both callbacks and return -EOPNOTSUPP for the unsupported
> operations.
> 
> Fixes: d734223b2f0d ("iavf: add initial framework for registering PTP clock")
> Link: https://docs.kernel.org/driver-api/ptp.html#writing-clock-drivers
> Link: https://lore.kernel.org/all/20260826101004.100979-1-xuanqiang.luo@linux.dev/
> Cc: stable@vger.kernel.org
> Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
> ---
>   drivers/net/ethernet/intel/iavf/iavf_ptp.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_ptp.c b/drivers/net/ethernet/intel/iavf/iavf_ptp.c
> index 87b97e09df14a..fcb273828bc1b 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_ptp.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_ptp.c
> @@ -252,6 +252,16 @@ static int iavf_ptp_gettimex64(struct ptp_clock_info *info,
>   	return iavf_read_phc_indirect(adapter, ts, sts);
>   }
>   
> +static int iavf_ptp_adjfine(struct ptp_clock_info *info, long scaled_ppm)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static int iavf_ptp_adjtime(struct ptp_clock_info *info, s64 delta)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
>   static int iavf_ptp_settime64(struct ptp_clock_info *info,
>   			      const struct timespec64 *ts)
>   {
> @@ -326,6 +336,8 @@ static int iavf_ptp_register_clock(struct iavf_adapter *adapter)
>   		 KBUILD_MODNAME, dev_name(dev));
>   	ptp_info->owner = THIS_MODULE;
>   	ptp_info->gettimex64 = iavf_ptp_gettimex64;
> +	ptp_info->adjfine = iavf_ptp_adjfine;
> +	ptp_info->adjtime = iavf_ptp_adjtime;
>   	ptp_info->settime64 = iavf_ptp_settime64;
>   	ptp_info->do_aux_work = iavf_ptp_do_aux_work;
>   
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>