The vulnerability in the Linux kernel involves the khugepaged subsystem, which manages transparent huge pages (THPs). Normally, files opened writable exclude THPs to avoid inconsistencies. However, an edge case allows collapse_file() to run concurrently with dirty folios from previous writes. When a file is opened writable, written to, closed, and then madvise() with MADV_COLLAPSE is called on a non-dirty range, followed by reopening the file writable, the kernel truncates the page cache and discards dirty folios, causing data loss. The fix involves fully writing back all dirty file pages and waiting for completion while holding the invalidate_lock, ensuring no dirty folios remain during THP collapse. Additionally, the nr_thps counter update was moved outside the i_pages lock for correctness.

This vulnerability can cause data loss due to dirty file pages being discarded during transparent huge page collapse operations on writable files. There is no indication of remote code execution or privilege escalation. The impact is limited to potential loss of data integrity for affected file operations.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vulnerability description indicates that the issue has been resolved in the Linux kernel by removing the problematic code and implementing a writeback mechanism before collapsing THPs. Users should monitor official Linux kernel releases and apply updates that include this fix once available.