CVE-2026-99218
Beschrijving NL
In the Linux kernel, the following vulnerability has been resolved:
coredump: hold RCU while releasing parked threads
coredump_finish() releases the parked threads by clearing ->task in
their core_thread entry and calling wake_up_process() on each of them. It does that without holding a reference on the task and without being
inside rcu. But calling wake_up_process(task) without rcu here isn't safe. A parked
thread doesn't need that wakeup to leave. A spurious wakeup or a
preemption after the store is enough for the task to go away. So if the coredump client is preempted between the store and
wake_up_process() the thread can exit and be freed in the meantime and
try_to_wake_up() takes pi_lock in freed memory. Hold rcu across the loop.
Origineel (Engels) tonen
In the Linux kernel, the following vulnerability has been resolved:
coredump: hold RCU while releasing parked threads
coredump_finish() releases the parked threads by clearing ->task in
their core_thread entry and calling wake_up_process() on each of them.
It does that without holding a reference on the task and without being
inside rcu.
But calling wake_up_process(task) without rcu here isn't safe. A parked
thread doesn't need that wakeup to leave. A spurious wakeup or a
preemption after the store is enough for the task to go away.
So if the coredump client is preempted between the store and
wake_up_process() the thread can exit and be freed in the meantime and
try_to_wake_up() takes pi_lock in freed memory.
Hold rcu across the loop.