CVE-2024-47669

In the Linux kernel, the following vulnerability has been resolved:

nilfs2: fix state management in error path of log writing function

After commit a694291a6211 (nilfs2: separate wait function from nilfs_segctor_write) was applied, the log writing function nilfs_segctor_do_construct() was able to issue I/O requests continuously even if user data blocks were split into multiple logs across segments, but two potential flaws were introduced in its error handling.

First, if nilfs_segctor_begin_construction() fails while creating the second or subsequent logs, the log writing function returns without calling nilfs_segctor_abort_construction(), so the writeback flag set on pages/folios will remain uncleared. This causes page cache operations to hang waiting for the writeback flag. For example, truncate_inode_pages_final(), which is called via nilfs_evict_inode() when an inode is evicted from memory, will hang.

Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared. As a result, if the next log write involves checkpoint creation, thats fine, but if a partial log write is performed that does not, inodes with NILFS_I_COLLECTED set are erroneously removed from the sc_dirty_files list, and their data and b-tree blocks may not be written to the device, corrupting the block mapping.

Fix these issues by uniformly calling nilfs_segctor_abort_construction() on failure of each step in the loop in nilfs_segctor_do_construct(), having it clean up logs and segment usages according to progress, and correcting the conditions for calling nilfs_redirty_inodes() to ensure that the NILFS_I_COLLECTED flag is cleared.

Affected Software

References

• https://git.kernel.org/stable/c/036441e8438b29111fa75008f0ce305fb4e83c0a
• https://git.kernel.org/stable/c/0a1a961bde4351dc047ffdeb2f1311ca16a700cc
• https://git.kernel.org/stable/c/30562eff4a6dd35c4b5be9699ef61ad9f5f20a06
• https://git.kernel.org/stable/c/3e349d7191f0688fc9808ef24fd4e4b4ef5ca876
• https://git.kernel.org/stable/c/40a2757de2c376ef8a08d9ee9c81e77f3c750adf
• https://git.kernel.org/stable/c/6576dd6695f2afca3f4954029ac4a64f82ba60ab
• https://git.kernel.org/stable/c/74866c16ea2183f52925fa5d76061a1fe7f7737b
• https://git.kernel.org/stable/c/efdde00d4a1ef10bb71e09ebc67823a3d3ad725b