In the Linux kernel, the following vulnerability has been resolved:
net: micrel: Fix receiving the timestamp in the frame for lan8841
The blamed commit started to use the ptp workqueue to get the second part of the timestamp. And when the port was set down, then this workqueue is stopped. But if the config option NETWORKPHYTIMESTAMPING is not enabled, then the ptpclock is not initialized so then it would crash when it would try to access the delayed work. So then basically by setting up and then down the port, it would crash. The fix consists in checking if the ptpclock is initialized and only then cancel the delayed work.