UBUNTU-CVE-2026-90409: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/panthor: Add vmbind region with kbo range overlap check When a VM is created, caller has to specify the range of the address space carve-out set aside for mapping kernel BO's. That means vmbind mappings of UM-exposed BO's should not intersect with that region, but at the moment we're not checking this. At first, I thought of giving these values to drmgpuvminit() through its reserve{offset, range} arguments, but it turns out that is meant for VM address spans that are not managed through the usual drmgpuvm split/merge circuit, so storing the end of the user VA range at VM creation time and doing a quick check in the vmbind ioctl path was the simplest workaround. The new check also makes sure vmbind range doesn't overflow the size of a 64-bit unsigned integer. That was already being done further down the call stack inside drmgpuvmsmmap -> drmgpuvmrangevalid, but it's best to fail early in the driver before GPUVM functions are invoked so that we won't waste time allocating vmbind context resources.