已配置debuginfod但GDB仍不显示符号的问题求助

调试服务启动时触发SIGSEGV错误，已配置debuginfod且GDB成功下载了系统库的调试信息，但堆栈跟踪中仍出现?? ()的无符号条目。启动GDB的命令为：

sudo DEBUGINFOD_URLS=https://debuginfod.archlinux.org gdb --args ./build/dns-wrapper --config-file config/config.ini

GDB相关输出如下：

GNU gdb (GDB) 15.1
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Reading symbols from ./build/dns-wrapper...
(gdb) r
Starting program: /home/ncd/git/dns-wrapper/build/dns-wrapper --config-file config/config.ini
Downloading separate debug info for /lib64/ld-linux-x86-64.so.2
Downloading separate debug info for system-supplied DSO at 0x7ffff7fc5000
Downloading separate debug info for /usr/lib/libboost_system.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_program_options.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_log_setup.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_log.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_thread.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_atomic.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_chrono.so.1.86.0
Downloading separate debug info for /usr/lib/libboost_filesystem.so.1.86.0
Downloading separate debug info for /usr/lib/libm.so.6
Downloading separate debug info for /usr/lib/libc.so.6
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Upstream server identified as: udp://1.1.1.1:53
Upstream server identified as: udp://8.8.8.8:53
[2024-09-28 18:53:39.662405] [0x00007ffff7d39940] [trace] [0x0008a1ea] [1] Dns Wrapper v0.0.0.1
[2024-09-28 18:53:39.662521] [0x00007ffff7d39940] [trace] [0x0008a1ea] [2] Git branch: win_raw_socket, Version: 01b16b2e-dirty, Commit: 01b16b2e-dirty, Date: 2024-09-28 10:24:37 +0530
[2024-09-28 18:53:39.662533] [0x00007ffff7d39940] [trace] [0x0008a1ea] [3] Current User: root
[2024-09-28 18:53:39.662540] [0x00007ffff7d39940] [trace] [0x0008a1ea] [4] Compiled for x86_64 (compiled locally) using cc (GCC) 14.2.1 20240910
[2024-09-28 18:53:39.662760] [0x00007ffff7d39940] [info] [0x0008a1ea] [5] Successfully read rules from file: ./rules.txt
[2024-09-28 18:53:39.662997] [0x00007ffff7d39940] [debug] [0x0008a1ea] [6] Skipping entering into daemon mode as per user request
[2024-09-28 18:53:39.663053] [0x00007ffff7d39940] [trace] [0x0008a1ea] [7] Daemon started on port: 10053

Program received signal SIGSEGV, Segmentation fault.
0x00005555555f43ed in boost::asio::detail::socket_ops::call_recvfrom<unsigned int> (s=8, data=0x7ffffffeab80, size=65535, flags=0, addr=0x7fffffffa740, 
    addrlen=0x7fffffffa890) at /usr/include/boost/asio/detail/impl/socket_ops.ipp:1130
1130    }
(gdb) where
#0  0x00005555555f43ed in boost::asio::detail::socket_ops::call_recvfrom<unsigned int> (s=8, data=0x7ffffffeab80, size=65535, flags=0, addr=0x7fffffffa740, 
    addrlen=0x7fffffffa890) at /usr/include/boost/asio/detail/impl/socket_ops.ipp:1130
#1  0x2851232006040001 in ?? ()
#2  0x00007fff0000fe51 in ?? ()
#3  0x0000000000000000 in ?? ()
(gdb) show debuginfod enabled
Debuginfod functionality is currently set to "on".
(gdb) show debuginfod urls
Debuginfod URLs are currently set to:
https://debuginfod.archlinux.org
(gdb) bt full
#0  0x00005555555f43ed in boost::asio::detail::socket_ops::call_recvfrom<unsigned int> (s=8, data=0x7ffffffeab80, size=65535, flags=0, addr=0x7fffffffa740, 
    addrlen=0x7fffffffa890) at /usr/include/boost/asio/detail/impl/socket_ops.ipp:1130
        tmp_addrlen = 20
        result = 561
#1  0x2851232006040001 in ?? ()
No symbol table info available.
#2  0x00007fff0000fe51 in ?? ()
No symbol table info available.
#3  0x0000000000000000 in ?? ()
No symbol table info available.

首先明确：堆栈中的?? ()不是因为符号未加载，而是程序崩溃时栈帧已被破坏——#1的地址0x2851232006040001不属于x86_64合法用户空间地址范围（通常为0x555555554000~0x7fffffffffff），说明栈内存已被非法写入篡改。

可按以下步骤排查：

• 检查崩溃点参数合法性：当前崩溃在boost::asio::detail::socket_ops::call_recvfrom，先验证参数：
  • 用info fd命令查看进程打开的文件描述符，确认s=8对应的是合法的UDP/TCP socket，且未被关闭。
  • 用x/x 0x7fffffffa890查看addrlen指针指向的内存值，确认是有效的sockaddr长度（如sockaddr_in对应16，sockaddr_in6对应28），且该内存区域未被越界覆盖。
• 生成并分析core dump：
  1. 在启动GDB的终端执行ulimit -c unlimited，设置core dump大小无限制。
  2. 程序崩溃后生成core文件，用gdb ./build/dns-wrapper core.xxx加载core文件，尝试获取更完整的栈信息（若core未被破坏）。
• 调整编译选项：确保编译程序时添加-g -O0参数，禁用优化并保留完整调试符号——优化编译会打乱栈帧结构，导致GDB无法正确解析调用栈。
• 排查多线程内存问题：若程序使用多线程，检查是否存在线程安全问题：
  • 确认socket资源未被多个线程同时读写。
  • 检查栈上变量是否被其他线程非法访问（如指针越界写入栈内存）。
• 启用GDB栈保护检查：在GDB中执行set canary on，启用栈金丝雀检查帮助定位栈溢出问题；也可用checksec ./build/dns-wrapper查看程序是否开启了栈保护编译选项。

内容的提问来源于stack exchange，提问作者slb