Linux kernel AMD XDNA driver: error path closes a live VMA and underflows its references

Impact

Two error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma) before returning an error, dropping the shmem pages_pin_count and the GEM object reference that back the VMA while the mmap syscall has not even returned. The VMA stays alive, so kernel teardown calls close() a second time when the process unmaps the range, producing a reference count underflow and freeing the backing object early. The record does not establish controllable exploitation beyond that underflow, but a local user who can make the page insertion fail can reach it. Applies only to hosts with AMD XDNA NPU hardware and the amdxdna driver loaded.

Who can reach it

A local user or container with access to the amdxdna accel device node, mmapping a buffer object under conditions where page insertion hits one of the error paths. No elevated privileges beyond device access.

What to do

Update to a stable kernel with the deferred-fault fix and reboot. In the interim, gate access to the amdxdna accel device node with a device cgroup rule so only workloads that actually use the NPU can reach the path; unloaded drivers are not exposed.

References

Related entries

• GPU / accelerator firmware (VBIOS, GSP, NVSwitch): GPU-resident firmware sits below the host OS and is not coveredNCVD-0000-012-gpu-accelerator-firmware-vbios-g · GPU / accelerator firmware (VBIOS, GSP, NVSwitch)Unscored
• NVIDIA Multi-Instance GPU (MIG) partitioning: MIG gives each instance its own SM slice, L2 slice, memory slice andNCVD-2020-001-nvidia-multi-instance-gpu-mig-pa · NVIDIA Multi-Instance GPU (MIG) partitioningUnscored
• NVIDIA Multi-Instance GPU (MIG) partitioning: MIG gives each instance its own SM slice, L2 slice, memory slice andNCVD-2020-003-nvidia-multi-instance-gpu-mig-pa · NVIDIA Multi-Instance GPU (MIG) partitioningUnscored
• Integrated GPU graphics data compression (Intel, AMD, Apple, Arm, Qualcomm, NVIDIA): GPUs apply data-dependent losslessNCVD-2023-003-integrated-gpu-graphics-data-com · Integrated GPU graphics data compression (Intel, AMD, Apple, Arm, Qualcomm, NVIDIA)Unscored
• NVIDIA Confidential Computing (H100/H200/B100/B200/GB200) - CC-DevTools operating mode: NVIDIA GPU confidentialNCVD-2023-004-nvidia-confidential-computing-h1 · NVIDIA Confidential Computing (H100/H200/B100/B200/GB200) - CC-DevTools operating modeUnscored
• Integrated GPU graphics data compression (Intel, AMD, Apple, Arm, Qualcomm, NVIDIA): GPUs apply data-dependent losslessNCVD-2023-005-integrated-gpu-graphics-data-com · Integrated GPU graphics data compression (Intel, AMD, Apple, Arm, Qualcomm, NVIDIA)Unscored