Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: iommufd: Take dma_resv lock before dma_buf_unpin() in release path… (CVE-2026-80633)

The Linux kernel's iommufd subsystem had a flaw where dma_buf_unpin() was called without holding the exporter's dma_resv lock in the release path (specifically in iopt_release_pages()). This violated the requirement that dma_buf_unpin() must be called with the dma_resv lock held, causing kernel warnings and potential stability issues. The patch ensures the dma_resv lock is taken around dma_buf_unpin() in iopt_release_pages(), matching the locking convention used in iopt_map_dmabuf(). dma_buf_detach() was correctly left outside the locked region as it acquires the lock internally.

The vulnerability could cause kernel warnings and potentially unstable behavior due to improper locking in the dma_buf unpinning process. The CVSS score of 8.8 indicates a high severity impact on confidentiality, integrity, and availability, but no known exploits are reported in the wild. The issue affects local attackers with low privileges and requires local access to trigger.

A fix is available that properly takes the dma_resv lock before calling dma_buf_unpin() in the iopt_release_pages() function. Users should apply the official Linux kernel patches that address this issue. Since this is a kernel-level vulnerability, updating to the patched kernel version is the recommended remediation.