ocfs2: prevent release journal inode after journal shutdown

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: prevent release journal inode after journal shutdown Before calling ocfs2_delete_osb(), ocfs2_journal_shutdown() has already been executed in ocfs2_dismount_volume(), so osb->journal must be NULL. Therefore, the following calltrace will inevitably fail when it reaches jbd2_journal_release_jbd_inode(). ocfs2_dismount_volume()-> ocfs2_delete_osb()-> ocfs2_free_slot_info()-> __ocfs2_free_slot_info()-> evict()-> ocfs2_evict_inode()-> ocfs2_clear_inode()-> jbd2_journal_release_jbd_inode(osb->journal->j_journal, Adding osb->journal checks will prevent null-ptr-deref during the above execution path.

References

• https://git.kernel.org/stable/c/42c415c53ad2065088cc411d08925effa5b3d255
• https://git.kernel.org/stable/c/e9188f66e94955431ddbe2cd1cdf8ff2bb486abf
• https://git.kernel.org/stable/c/f4a917e6cd6c798f7adf39907f117fc754db1283
• https://git.kernel.org/stable/c/85e66331b60601d903cceaf8c10a234db863cd78
• https://git.kernel.org/stable/c/f46e8ef8bb7b452584f2e75337b619ac51a7cadf