fatal error: stack overflow

runtime stack:
runtime.throw({0xfd1b47?, 0x7d6dbc3aa808?})
	GOROOT/src/runtime/panic.go:1229 +0x38 fp=0x7d6dbc7ade80 sp=0x7d6dbc7ade50 pc=0x96428
runtime.newstack()
	GOROOT/src/runtime/stack.go:1178 +0x498 fp=0x7d6dbc7adfb0 sp=0x7d6dbc7ade80 pc=0x7b5f8
runtime.morestack()
	src/runtime/asm_arm64.s:507 +0x70 fp=0x7d6dbc7adfb0 sp=0x7d6dbc7adfb0 pc=0x9caa0