CVE-2023-53804

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

nilfs2: fix use-after-free bug of nilfsroot in nilfsevict_inode()

During unmount process of nilfs2, nothing holds nilfsroot structure after nilfs2 detaches its writer in nilfsdetachlogwriter(). However, since nilfsevictinode() uses nilfsroot for some cleanup operations, it may cause use-after-free read if inodes are left in "garbagelist" and released by nilfsdisposelist() at the end of nilfsdetachlog_writer().

Fix this issue by modifying nilfsevictinode() to only clear inode without additional metadata changes that use nilfs_root if the file system is degraded to read-only or the writer is detached.