CVE-2026-98178

drm/amdgpu: Skip KFD mapping clear before initialization

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Skip KFD mapping clear before initialization amdgpu_amdkfd_clear_kfd_mapping() assumes that a non-NULL kfd_dev has a fully populated node array. This is not true when KFD device initialization fails after probe. For example, kgd2kfd_device_init() sets num_nodes before checking PCIe atomics support. On Polaris systems without the required atomics, it returns before allocating nodes[0], but the kfd_dev remains attached to the amdgpu device. A later GPU reset then dereferences nodes[0]->id. Require the authoritative KFD initialization flag before walking the node array, matching the existing KFD reset and teardown paths. (cherry picked from commit 4ac1835823c47903fbb278bbf474773c46f59edc)