In the Linux kernel, the following vulnerability has been resolved:

drm/vmwgfx: reject DX_BIND_QUERY without a DX context

vmw_cmd_dx_bind_query() unconditionally dereferences
sw_context->dx_ctx_node->ctx.  Userspace can trigger a NULL pointer
dereference from any render-node fd by submitting an execbuf with
dx_context_handle == SVGA3D_INVALID_ID and a SVGA_3D_CMD_DX_BIND_QUERY
opcode in the command stream: dx_ctx_node is left NULL and the kernel
oopses on the assignment.  The same NULL is then re-read in
vmw_resources_reserve() via vmw_context_get_dx_query_mob().

All sibling DX handlers fail-close on a missing dx_ctx_node using
VMW_GET_CTX_NODE().  Use the same pattern here, returning -EINVAL up
front before any relocation state is published.