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

netfs, afs: Fix write skipping in dir/link writepages

Fix netfs_write_single() and afs_single_writepages() to better handle a
write that would be skipped due to lock contention and WB_SYNC_NONE by
returning 1 from netfs_write_single() if it skipped and making
afs_single_writepages() skip also.  If a skip occurs, the inode must be
re-marked as the VFS may have cleared the mark.

This is really only theoretical for directories in netfs_write_single() as
the only path to that is through afs_single_writepages() that takes the
->validate_lock around it, thereby serialising it.