[Bug] 多线程情况下触发用户态代码段的缺页异常处理失败

RT-Thread Version

master

Hardware Type/Architectures

qemu-virt64-riscv/k230

Develop Toolchain

GCC

Describe the bug

触发问题的代码

#include <atomic>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <thread>
#include <unistd.h>
#include <vector>

using namespace std;

atomic_flag lock_stream = ATOMIC_FLAG_INIT;

void append_number_unlock(int x)
{
    int num;
    cout << "https://www";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << ".rt-";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << "thread";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << ".org/";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << setw(3) << setfill('0') << x << endl;
}

void append_number_lock(int x)
{
    while (lock_stream.test_and_set()) {
    }
    int num;
    cout << "https://www";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << ".rt-";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << "thread";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << ".org/";
    for (int i = 0; i < 1000000; i++)
        num++;
    cout << setw(3) << setfill('0') << x << endl;
    lock_stream.clear();
}

void string_split(const string &str, const char split, vector<string> &res)
{
    if (str == "")
        return;
    // 在字符串末尾也加入分隔符，方便截取最后一段
    string strs = str + split;
    size_t pos  = strs.find(split);

    // 若找不到内容则字符串搜索函数返回 npos
    while (pos != strs.npos) {
        string temp = strs.substr(0, pos);
        res.push_back(temp);
        // 去掉已分割的字符串,在剩下的字符串中进行分割
        strs = strs.substr(pos + 1, strs.size());
        pos  = strs.find(split);
    }
}

int main()
{
    cout << "un_lock" << endl;
    vector<thread> threads_unlock;
    for (int i = 1; i <= 20; ++i)
        threads_unlock.push_back(thread(append_number_unlock, i));
    for (auto &th : threads_unlock)
        th.join();
    cout << "lock" << endl;

    stringstream ss;
    streambuf   *buffer = cout.rdbuf();
    cout.rdbuf(ss.rdbuf());

    vector<thread> threads_lock;
    for (int i = 1; i <= 20; ++i)
        threads_lock.push_back(thread(append_number_lock, i));
    for (auto &th : threads_lock)
        th.join();

    cout.rdbuf(buffer);
    string s(ss.str());
    cout << s << endl;

    vector<string> str_list;
    string_split(s, '\n', str_list);
    bool b = true;
    for (auto str : str_list) {
        cout << str.length() << " ";
        if (str != "")
            if (str.length() != 29) {
                b = false;
            }
    }

    if (b)
        printf("{Test PASS}.\n");
    else
        printf("{Test FAIL}.\n");

    return 0;
}

编译器

针对k230带V指令的gcc13(通用编译器gcc10无法触发)

• 编译参数: -static

现象描述

当两个线程同时触发同一指令地址的缺页异常时，一个线程成功映射页，另一个线程处理这个异常时被判定为权限问题导致异常处理失败

Other additional context

No response

Reproduce the case on qemu-virt64-riscv/k230 with GCC 13 and the provided multithreaded C++ program, then trace the user-mode page-fault handling path for simultaneous faults at one instruction address. Done means both threads resolve the fault successfully when one thread has already mapped the page, without the second fault being misclassified as a permission error.