CVE-2025-68771

/// Technical description

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

ocfs2: fix kernel BUG in ocfs2_find_victim_chain

syzbot reported a kernel BUG in ocfs2_find_victim_chain() because the

`cl_next_free_rec` field of the allocation chain list (next free slot in

the chain list) is 0, triggring the BUG_ON(!cl->cl_next_free_rec)

condition in ocfs2_find_victim_chain() and panicking the kernel.

To fix this, an if condition is introduced in ocfs2_claim_suballoc_bits(),

just before calling ocfs2_find_victim_chain(), the code block in it being

executed when either of the following conditions is true:

1. `cl_next_free_rec` is equal to 0, indicating that there are no free

chains in the allocation chain list

2. `cl_next_free_rec` is greater than `cl_count` (the total number of

chains in the allocation chain list)

Either of them being true is indicative of the fact that there are no

chains left for usage.

This is addressed using ocfs2_error(), which prints

the error log for debugging purposes,

/// 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