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

ring-buffer: Add checking nr_subbufs to persistent ring buffer validation

Sashiko reported that the code was using meta->nr_subbufs without making
sure that it matched the nr_pages + 1 on data that was assuming the two
were the same.

Add a check to the persistent ring buffer validation code to make sure
that the saved nr_subbufs matches what we expect.