CVE-2026-89500

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

ring-buffer: Make cpu buffer::free page a buffer data read page

Discarding a cached reader page after a concurrent ring buffer resize uses the new global subbuf order for the free pages() call. This mismatched order may crashes the kernel or leaks memory because the cached page was allocated under the old size.

Save the actual free page order alongside the page address to ensure we always refer to the correct value and do not rely on the potentially stalled cpu buffer->subbuf order value. The simplest is to make free page a buffer data read page which already covers exactly what we need: a page address and a page order.