Linux C++使用GDB调试动态库崩溃问题的完全指南

# GCC编译选项
-g -O0
# CMake配置示例
target_compile_options(your_library PRIVATE -g -O0)

# 临时启用核心转储，设置核心文件大小无限制
ulimit -c unlimited

# 永久启用核心转储，编辑/etc/security/limits.conf添加
* soft core unlimited
* hard core unlimited

# 设置核心文件命名格式和存储位置
echo "core.%e.%p.%h.%t" > /proc/sys/kernel/core_pattern
echo "/var/crash/" > /proc/sys/kernel/core_uses_pid

Segmentation fault (core dumped)
Aborted (core dumped)
Illegal instruction (core dumped)

# 基本用法
gdb ./your_program -c ./core_file

# 查看崩溃时的调用栈
bt
# 或使用full查看详细信息
bt full

#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=136183322302016) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=136183322302016) at ./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=136183322302016, signo=signo@entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007bdba8642476 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007bdba86287f3 in __GI_abort () at ./stdlib/abort.c:79
#5  0x00007bdba8aa2b9e in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
#6  0x00007bdba8aae20c in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
#7  0x00007bdba8aae277 in std::terminate() () from /lib/x86_64-linux-gnu/libstdc++.so.6
#8  0x00007bdba8aae4d8 in __cxa_throw () from /lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x00007bdbaa1d9b25 in Data::hasEvent(dataChangeEvent&) () from /usr/ems/lib/libstgy.so
#10 0x00007bdbaa1dd37a in DeviceBase::update() () from /usr/ems/lib/libstgy.so
#11 0x00007bdbaa244826 in IDataModel::updateLocked() () from /usr/ems/lib/libstgy.so
#12 0x00007bdbaa24884f in CoreDataModule::updateImpl() () from /usr/ems/lib/libstgy.so
#13 0x00007bdbaa12c87f in IDataModule::update() () from /usr/ems/lib/libstgy.so
#14 0x00007bdbaa13da81 in DataSvc::svc() () from /usr/ems/lib/libstgy.so
#15 0x00007bdbaa380477 in Task::_start() () from /usr/ems/lib/libstgy.so

info sharedlibrary

set solib-search-path /path/to/your/library/directory

set solib-search-path /usr/ems/lib

add-symbol-file /usr/ems/lib/libstgy.so 0x00007bdbaa1259b0

# 查看当前函数的局部变量
info locals

# 查看特定变量的值
print variable_name

# 查看内存内容
x/10xw memory_address

# 查看寄存器状态
info registers

# 显示当前位置的源代码
list

# 显示特定函数的源代码
list MyDynamicLibrary::processData

# 显示特定行范围的代码
list 100,200

// 动态库中的错误代码
void processData(char* data) {
    *data = 'a'; // data可能为NULL
}

# 崩溃后查看data变量的值
print data
# 如果为0x0，则确认是空指针问题

// 动态库中的错误代码
void processArray(int* arr, int size) {
    for (int i = 0; i <= size; i++) { // 错误：i <= size 应该是 i < size
        arr[i] = i;
    }
}

# 设置观察点检测内存访问
watch *arr@size+1
# 继续执行，观察何时越界
continue

// 动态库中的错误代码
int calculate() {
    int result;
    // 忘记初始化result
    return result * 2;
}

# 查看变量值
print result
# 如果值是随机的，说明未初始化

# 检查程序使用的动态库版本
ldd ./your_program

# 检查动态库符号
nm -D ./libmydynamiclibrary.so | grep function_name

# 设置动态库搜索路径
set solib-search-path /path/to/libraries

# 加载核心文件
core-file ./core_file

# 显示调用栈
bt full

# 查看寄存器
info registers

# 保存调试信息到文件
set logging file gdb_debug.log
set logging on

gdb -x gdb_script.gdb ./your_program

# 查看所有线程信息
info threads

# 切换到特定线程
thread thread_id

# 查看所有线程的调用栈
thread apply all bt

g++ -g -fsanitize=address -fno-omit-frame-pointer -o libmydynamiclibrary.so -shared source_files.cpp

gdb ./main ./core.main.12345

(gdb) bt
#0  0x00007f8b8a6b23c0 in UserDataProcessor::processUserData(UserData*) () from ./libuserdata.so
#1  0x00005567a8901234 in main () at main.cpp:42

(gdb) list UserDataProcessor::processUserData
100  void UserDataProcessor::processUserData(UserData* userData) {
101      // 处理用户数据
102      if (userData->age > 18) {
103          // 成年人逻辑
104      }
105  }

(gdb) print userData
$1 = (UserData *) 0x0

void UserDataProcessor::processUserData(UserData* userData) {
    if (userData == nullptr) {
        // 处理错误情况
        return;
    }
    if (userData->age > 18) {
        // 成年人逻辑
    }
}