On Thu, Jan 23, 2025 at 08:22:40AM +0100, Thomas Weißschuh wrote:
> The ioctl and sysfs handlers unconditionally call the ->enable callback.
> Not all drivers implement that callback, leading to NULL dereferences.
> Example of affected drivers: ptp_s390.c, ptp_vclock.c and ptp_mock.c.
>
> Instead use a dummy callback if no better was specified by the driver.
>
> Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> ---
> drivers/ptp/ptp_clock.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
> index b932425ddc6a3789504164a69d1b8eba47da462c..35a5994bf64f6373c08269d63aaeac3f4ab31ff0 100644
> --- a/drivers/ptp/ptp_clock.c
> +++ b/drivers/ptp/ptp_clock.c
> @@ -217,6 +217,11 @@ static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
> return info->gettime64(info, ts);
> }
>
> +static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> static void ptp_aux_kworker(struct kthread_work *work)
> {
> struct ptp_clock *ptp = container_of(work, struct ptp_clock,
> @@ -294,6 +299,9 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
> ptp->info->getcrosscycles = ptp->info->getcrosststamp;
> }
>
> + if (!ptp->info->enable)
> + ptp->info->enable = ptp_enable;
> +
> if (ptp->info->do_aux_work) {
> kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
> ptp->kworker = kthread_run_worker(0, "ptp%d", ptp->index);
>
> ---
> base-commit: c4b9570cfb63501638db720f3bee9f6dfd044b82
> change-id: 20250122-ptp-enable-831339c62428
>
> Best regards,
> --
> Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
What about other ops, did you check it too? Looks like it isn't needed,
but it sometimes hard to follow.
Thanks
