On 2025-01-23 10:38:37+0100, Michal Swiatkowski wrote:
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@vger.kernel.org Signed-off-by: Thomas Weißschuh linux@weissschuh.net
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@weissschuh.net
Reviewed-by: Michal Swiatkowski michal.swiatkowski@linux.intel.com
What about other ops, did you check it too? Looks like it isn't needed, but it sometimes hard to follow.
I couldn't find any missing, but I'm not familiar with the subsystem and didn't check too hard.
Note:
A follow-up fix would be to actually guard the users of ->enable and error out. For sysfs the attributes could be hidden completely. That would be a nicer user interface but more code change which are not so easily backportable.
Thomas