CVE-2026-99158

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

ring-buffer: Fix false warning in ring buffer map get reader()

The mmap reader can warn when it catches up with a writer that is still committing events. rb get reader page() returns NULL in this case, but ring buffer map get reader() treats that result as an error.

The initial rb per cpu empty() check filters out an empty buffer, but it does not guarantee that the next reader page has committed data. Writers do not take reader lock and can advance commit page before publishing the committed length on the new page. rb get reader page() can swap to that page, catch up with the writer and return NULL.

Handle NULL through the existing no-data exit without warning. Remove the caller's reader page == commit page check as well, since the reader-page helper already handles that case. The existing metadata update and return path remain in place.