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

[Jacob Keller <jacob.e.keller@intel.com>]

On 8/28/2026 2:10 AM, Vadim Fedorenko wrote:
> 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>

Acked-by: Jacob Keller <jacob.e.keller@intel.com>

>> ---
>>   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>