In the Linux kernel, the following vulnerability has been resolved: mm: cachestat: fix folio read-after-free in cache walk In cachestat, we access the folio from the page cache's xarray to compute …

Summary

In the Linux kernel, the following vulnerability has been resolved: mm: cachestat: fix folio read-after-free in cache walk In cachestat, we access the folio from the page cache's xarray to compute its page offset, and check for its dirty and writeback flags. However, we do not hold a reference to the folio before performing these actions, which means the folio can concurrently be released and reused as another folio/page/slab. Get around this altogether by just using xarray's existing machi…