stat_size=5368696832 (64-bit inf_len honored)
pread@0 -> 32 bytes 0xBB (extent1 marker, correct)
pread@0xffffc000 -> ret=0 (int fsize gate: reads >= 268431360 return EOF)
pread@0x100000000 -> ret=0 (silent EOF, no wrong-data return)
mmap@0 -> EINVAL (v_object NULL for ALL udf files; also @4G)
guest alive

env: DragonFly 6.5-DEVELOPMENT INVARIANTS kernel, QEMU/KVM 6 vCPU, 4GB RAM