CVE-2026-99218coredump: hold RCU while releasing parked threads

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/fd0fbe84312fda2fc187428c92c50b7d03a9d24c
• https://git.kernel.org/stable/c/71146c437bae59e5280f657965dc6d006ee3989b
• https://git.kernel.org/stable/c/0fce73efee40c65ce26641c5d93942462f9e8307
• https://git.kernel.org/stable/c/16e94ed90b1b02398e044d41fd1db34828daa08e
• https://git.kernel.org/stable/c/a0f09ff4c6b93312e565cfe75d76c3a551a3ec4c
• https://git.kernel.org/stable/c/b0eca0edddf4c1dbaf6d1f6a8636b4235f5bc573
• https://git.kernel.org/stable/c/61d58591aa0188bf2463e263962256316ff8b576