In the Linux kernel, the following vulnerability has been resolved:
ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
During unmount, ocfs2_journal_shutdown() frees the journal and sets osb->journal to NULL. Later, when VFS evicts remaining cached inodes, ocfs2_evict_inode() -> ocfs2_clear_inode() -> ocfs2_checkpoint_inode() -> ocfs2_ci_fully_checkpointed() dereferences osb->journal, causing a NULL pointer dereference.
Fix this by adding a NULL check for osb->journal in ocfs2_checkpoint_inode(). If the journal is NULL, it has already been fully flushed and destroyed during shutdown, so there is nothing to checkpoint.
References
- https://git.kernel.org/stable/c/24daf13422e8328fd588c34a017bdef1949910e8
- https://git.kernel.org/stable/c/499714de42ab4d2e778cbb10186684142a1222eb
- https://git.kernel.org/stable/c/63921f790234b221e4b15c56c72888b13250f81d
- https://git.kernel.org/stable/c/7da7e4ac21895fe34cceffcfc99497cc2750da99
- https://git.kernel.org/stable/c/a291c77c034b7a81849ce9b71cc9ecda9e587d89
- https://git.kernel.org/stable/c/eb6a13834c23e291f1170cb1b489ec255edfa5a3