Question

每个 G 对象都自带一块栈内存（stack），默认 2KB。

// stack.go

// The minimum size of stack used by Go code
_StackMin = 2048

栈内存地址范围 [stack.lo, stack.hi) 。

// proc.go

// Allocate a new g, with a stack big enough for stacksize bytes.

func malg(stacksize int32) *g {
    newg := new(g)
    
    if stacksize >= 0 {
        stacksize = round2(_StackSystem + stacksize)
        systemstack(func() {
            newg.stack = stackalloc(uint32(stacksize))
        })
        
        newg.stackguard0 = newg.stack.lo + _StackGuard
        newg.stackguard1 = ^uintptr(0)
    }
    
    return newg
}