amdgpu userptr, which RADV uses for VK_EXT_external_memory_host, refuses
file-backed VMAs (libdrm sets AMDGPU_GEM_USERPTR_ANONONLY). The executable's
writable PT_LOAD mappings are file-backed MAP_PRIVATE, so on RADV they are
never imported and become writable image mirrors that every address-based
build compares in full.
At load, libc replaces each rw-p mapping of /proc/self/exe with an anonymous
copy at the same address, before any guest code runs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>