nilfs2: fix NULL i_assoc_inode dereference in nilfs_mdt_save_to_shadow_map

Summary

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix NULL i_assoc_inode dereference in nilfs_mdt_save_to_shadow_map The DAT inode's btree node cache (i_assoc_inode) is initialized lazily during btree operations. However, nilfs_mdt_save_to_shadow_map() assumes i_assoc_inode is already initialized when copying dirty pages to the shadow map during GC. If NILFS_IOCTL_CLEAN_SEGMENTS is called immediately after mount before any btree operation has occurred on the DAT inode, i_assoc_inode is NULL leading to a general protection fault. Fix this by calling nilfs_attach_btree_node_cache() on the DAT inode in nilfs_dat_read() at mount time, ensuring i_assoc_inode is always initialized before any GC operation can use it.

Timeline

1. Apr 24, 2026, 2:42 PM UTCCVE published
2. Jun 14, 2026, 5:42 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 5.10.118 · fixed in 5.10.258; From 5.15.42 · fixed in 5.15.209; From 4.14.296 · fixed in 4.15; From 4.19.245 · fixed in 4.20; From 5.4.196 · fixed in 5.5; From 5.17.10 · fixed in 5.18

• Linux Linux

  5.18

References 9