CVE-2026-89830

/// Technical description

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

f2fs: fix valid block count leak on data block allocation failure

In __allocate_data_block(), when allocating a new data block

(dn->data_blkaddr == NULL_ADDR), inc_valid_block_count() is

called first to increment total_valid_block_count and i_blocks.

If the subsequent f2fs_allocate_data_block() fails, the function

returns the error directly without rolling back the

already-incremented block counts, causing a permanent leak.

Fix this by calling dec_valid_block_count() to undo the

increment before returning the error. The condition

old_blkaddr == NULL_ADDR precisely identifies the case where

inc_valid_block_count() was called.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References