有人能解释一下为什么我的代码在ReentrantMutexGuard上执行borrow_mut()时会死机吗？这是我的代码

use std::sync::Mutex;
use std::cell::RefCell;

use parking_lot::ReentrantMutex;

#[derive(Default)]
struct InnerData {
    ia: i32,
    ib: i32,
}

#[derive(Default)]
struct OuterData {
    oa: i32,
    ob: ReentrantMutex<RefCell<InnerData>>,
}

impl OuterData {
    fn foo(&self) {
        println!("fn foo begin");
        let mut b_mg = self.ob.lock();
        let mut b_data = b_mg.borrow_mut();
        println!("after acquiring lock");
        if b_data.ia == 3 {
            b_data.ib = 5;
        }
        println!("fn foo end");
    }
}

fn main() {
    let mut outer_data: OuterData = Default::default();
    let mut b_mg = outer_data.ob.lock();
    let mut b_data = b_mg.borrow_mut();
    b_data.ia = 3;

    if b_data.ia == 3 {
        outer_data.foo();
    }
}