CVE-2025-71185

What it actually does

Failure to drop the reference taken on the crossbar platform device during am335x route allocation in the dmaengine ti driver causes a device reference leak.

Why it matters to the business

On affected embedded Linux systems using TI AM335x hardware, repeated route allocations can gradually exhaust memory resources, degrading stability of long-running processes over time.

How an attack unfolds

An attacker with local access on an affected AM335x system repeatedly triggers DMA crossbar route allocations; each allocation takes a device reference that is never released, accumulating unreclaimed objects until memory pressure affects availability.

How to fix it

Upgrade to linux-virt 6.12.35-r0 or later, linux-virt-doc 6.12.35-r0 or later, or apply the kernel commit 1befa553f1ecc045dc9ff56107ff50162f63f3c0 in the stable tree; rebuild and deploy the updated kernel packages.

How to confirm the fix worked

Verify the running kernel contains commit 1befa553f1ecc045dc9ff56107ff50162f63f3c0 or is at version 6.12.35-r0 or newer; inspect dmaengine/ti/dma-crossbar.c for the reference drop after platform device lookup.

Typical attack path

1. Gain local user access to the target system
2. Trigger repeated am335x DMA route allocation paths in the dma-crossbar driver
3. Accumulate leaked device references over time
4. Induce memory pressure that impacts system stability

How to detect it

Review kernel memory statistics and slab usage on AM335x platforms for unexpected growth in platform_device or dmaengine-related objects; correlate with logs showing repeated am335x route allocation activity.

What your security team should do

• Apply the listed fixed kernel versions immediately on all AM335x-based deployments
• Monitor memory usage trends on affected devices pending patch rollout
• Restrict local access to systems running vulnerable kernels where feasible