CVE-2026-64232

Summary

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

block: recompute nr_integrity_segments in blk_insert_cloned_request

blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "the queue settings related to segment counting may differ from the original queue." The exact same reasoning applies to integrity segments: a stacked driver's underlying queue can have tighter virt_boundary_mask, seg_boundary_mask, or max_segment_size than the top queue, in which case blk_rq_count_integrity_sg() against the bottom queue produces a different count than the cached rq->nr_integrity_segments inherited from the source request by blk_rq_prep_clone().

When the cached count is lower than the bottom queue's actual count, blk_rq_map_integrity_sg() trips

BUG_ON(segments > rq->nr_integrity_segments);

on dispatch. The same families of stacked setups that motivated the existing nr_phys_segments recompute – dm-multipath fanning out to nvme-rdma in particular – can produce this.

Mirror the nr_phys_segments handling: when the request carries integrity, recompute nr_integrity_segments against the bottom queue and reject the request if it exceeds the bottom queue's max_integrity_segments. blk_rq_count_integrity_sg() and queue_max_integrity_segments() are both already available via <linux/blk-integrity.h>, which blk-mq.c includes.

This closes a latent gap in the stacking contract and brings the integrity-segment accounting in line with the existing phys-segment accounting.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/53a01bcc0242590eda4c452a5bd996f62457113b
• https://git.kernel.org/stable/c/0943f81e1b3176f27dbaf6db268fc69d8a94f0ba
• https://git.kernel.org/stable/c/42929c98d044f126508baf54a65b0f87f932fa75
• https://git.kernel.org/stable/c/2c6e6a18a37b905cb584eb0dda3ae482162a81ca

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