nilfs2: prevent use of deleted inode
In the Linux kernel, the following vulnerability has been resolved: nilfs2: prevent use of deleted inode syzbot reported a WARNING in nilfs_rmdir. [1] Because the inode bitmap is corrupted, an inode with an inode number that should exist as a ".nilfs" file was reassigned by nilfs_mkdir for "file0", causing an inode duplication during execution. And this causes an underflow of i_nlink in rmdir operations. The inode is used twice by the same task to unmount and remove directories ".nilfs" and "file0", it trigger warning in nilfs_rmdir. Avoid to this issue, check i_nlink in nilfs_iget(), if it is 0, it means that this inode has been delete
- Update to 5.15.0-1077.83~20.04.1