Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages() Two error… (CVE-2026-74721)

CVE-2026-74721 addresses a flaw in the Linux kernel's accel/amxdna component where two error paths in amdxdna_insert_pages() incorrectly called vma->vm_ops->close(vma) before returning an error. Since amdxdna_gem_obj_mmap() registers an HMM interval notifier before calling amdxdna_insert_pages(), manually invoking vm_ops->close() prematurely drops the shmem pages_pin_count and GEM object reference backing the VMA while it is still alive. This leads to a reference count underflow when the kernel later calls vm_ops->close() again during VMA teardown. The fix replaces the hard-error returns with a deferred-fault mechanism that keeps the VMA alive and retries page insertion via the HMM range-fault path.

The vulnerability can cause a reference count underflow in the kernel's memory management subsystem, potentially leading to memory corruption or instability. The CVSS score of 7.8 indicates high impact on confidentiality, integrity, and availability. However, exploitation requires local privileges and low complexity. There are no known exploits in the wild.

A fix for this vulnerability has been implemented in the Linux kernel. Users should apply the official kernel updates that include the corrected amdxdna_insert_pages() error handling. Since this is a kernel-level fix, upgrading to the patched kernel version is the recommended remediation. No additional mitigations are specified.