CVE-2025-71295

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> fs/buffer: add alert in try_to_free_buffers() for folios without buffers<br /> <br /> try_to_free_buffers() can be called on folios with no buffers attached<br /> when filemap_release_folio() is invoked on a folio belonging to a mapping<br /> with AS_RELEASE_ALWAYS set but no release_folio operation defined.<br /> <br /> In such cases, folio_needs_release() returns true because of the<br /> AS_RELEASE_ALWAYS flag, but the folio has no private buffer data. This<br /> causes try_to_free_buffers() to call drop_buffers() on a folio with no<br /> buffers, leading to a null pointer dereference.<br /> <br /> Adding a check in try_to_free_buffers() to return early if the folio has no<br /> buffers attached, with WARN_ON_ONCE() to alert about the misconfiguration.<br /> This provides defensive hardening.