fatal error: stack overflow

runtime stack:
runtime.throw({0xe8e740?, 0x20?})
	GOROOT/src/runtime/panic.go:1077 +0x40 fp=0x40012d9e00 sp=0x40012d9dd0 pc=0x4a090
runtime.newstack()
	GOROOT/src/runtime/stack.go:1107 +0x458 fp=0x40012d9fb0 sp=0x40012d9e00 pc=0x65968
runtime.morestack()
	src/runtime/asm_arm64.s:316 +0x70 fp=0x40012d9fb0 sp=0x40012d9fb0 pc=0x7f4e0