ice: Don't process extts if PTP is disabled

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ice: Don't process extts if PTP is disabled The ice_ptp_extts_event() function can race with ice_ptp_release() and result in a NULL pointer dereference which leads to a kernel panic. Panic occurs because the ice_ptp_extts_event() function calls ptp_clock_event() with a NULL pointer. The ice driver has already released the PTP clock by the time the interrupt for the next external timestamp event occurs. To fix this, modify the ice_ptp_extts_event() function to check the PTP state and bail early if PTP is not ready.

References

• https://git.kernel.org/stable/c/1c4e524811918600683b1ea87a5e0fc2db64fa9b
• https://git.kernel.org/stable/c/996422e3230e41468f652d754fefd1bdbcd4604e