Hello,
Lack of proper validation that cached inodes are free during allocation can, cause a crash in fs/xfs/xfs_icache.c (refer: CVE-2018-13093). To address this issue, I'm backporting upstream commit [1] to 4.4 and 4.9 stable trees (a backport of [1] to 4.14 already exists).
Also, commit [1] references another commit [2] which added checks only to xfs_iget_cache_miss(). In this patch, those checks have been moved into a dedicated checker method and both xfs_iget_cache_miss() and xfs_iget_cache_hit() are made to call that method. This code reorg in commit [1], makes commit [2] redundant in the history of the 4.9 and 4.4 stable trees. So commit [2] is not being backported.
-- Sid
[1]: afca6c5b2595 ("xfs: validate cached inodes are free when allocated") [2]: ee457001ed6c ("xfs: catch inode allocation state mismatch corruption")
change log: v2: - Reword cover letter. - Fix accidental worong patch that got mailed.