Linux EUVD-2026-59493

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

RDMA/irdma: Fix OOB read during CQ MR registration

Sashiko pointed out an unrelated bug during a previous patch: https://sashiko.dev/#/patchset/20260512183852.614045-1-jmoroni%40google.com

This change fixes the bug by eliminating the cqmr->split field which was not being set properly and instead just checks the CQ resize feature flag directly.

The cqmr->split field essentially tracks whether IRDMA_FEATURE_CQ_RESIZE is set, but it was not being set until CQ creation time, which is _after_ CQ memory registration (the only other place where it is referenced).

As a result, it would always be false during MR registration and would therefore cause irdma_handle_q_mem to populate cqmr->shadow even for GEN_2 HW and beyond:

cqmr->shadow = (dma_addr_t)arr[req->cq_pages];

The issue is that for GEN_2 and beyond, req->cq_pages may be exactly equal to iwmr->page_cnt and therefore equal to the size of arr, which would cause an OOB read by one.