I think its supposed to be _start and not start ` global _start

section .text

_start: mov rax, 0x20000004 mov rdi, 1 lea rsi, [rel msg] mov rdx, msg.len syscall

mov rax, 0x20000001
mov rdi, 0
syscall

section .data

msg: db "Hello, World!", 10 .len: equ $ - msg `