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.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-4-vdonnefort@google.com
Fixes: 8e7b58c27b3c ("ring-buffer: Just update the subbuffers when changing their allocation order")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

0 files changed, 0 insertions, 0 deletions