CVE-2025-39859

In the Linux kernel, the following vulnerability has been resolved:

ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog

The ptp_ocp_detach() only shuts down the watchdog timer if it is

pending. However, if the timer handler is already running, the

timer_delete_sync() is not called. This leads to race conditions

where the devlink that contains the ptp_ocp is deallocated while

the timer handler is still accessing it, resulting in use-after-free

bugs. The following details one of the race scenarios.

(thread 1) | (thread 2)

ptp_ocp_remove() |

ptp_ocp_detach() | ptp_ocp_watchdog()

if (timer_pending(&bp->watchdog))| bp = timer_container_of()

timer_delete_sync() |

|

devlink_free(devlink) //free |

| bp-> //use

Resolve this by unconditionally calling timer_delete_sync() to ensure

the timer is reliably deactivated, preventing any access after free.