In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid potential deadloop in f2fs_fsync_node_pages()
There is potential deadloop in race condition:
Thread A Thread B
- fsync
- f2fs_do_sync_file
- f2fs_fsync_node_pages
- last_fsync_dnode
- folio_get(last_folio)
- f2fs_setattr
- f2fs_truncate
- f2fs_truncate_blocks
- f2fs_do_truncate_blocks
- f2fs_truncate_inode_blocks
- truncate_dnode
- truncate_node
- invalidate_mapping_pages
- folio->mapping = NULL
- is_node_folio alwasy return false
- atomic && !marked is always true,
then goto retry