Oracle Linux: CVE-2025-21786: ELSA-2025-20095-0: kernel security update (MODERATE) (Multiple Advisories)

In the Linux kernel, the following vulnerability has been resolved:
workqueue: Put the pwq after detaching the rescuer from the pool
The commit 68f83057b913("workqueue: Reap workers via kthread_stop() and
remove detach_completion") adds code to reap the normal workers but
mistakenly does not handle the rescuer and also removes the code waiting
for the rescuer in put_unbound_pool(), which caused a use-after-free bug
reported by Cheung Wall.
To avoid the use-after-free bug, the pool’s reference must be held until
the detachment is complete. Therefore, move the code that puts the pwq
after detaching the rescuer from the pool.
A vulnerability was found in the Linux kernel's work queue subsystem, which manages background task execution. The issue stems from improper handling of the "rescuer" thread during the cleanup of unbound work queues.