问题描述
为什么在为 min_alloc_size 的构造函数设置 boost::pool<> 时此代码 snippet encounter 段错误，而它在不设置所述参数的情况下运行良好？
这是代码片段：
#include <boost/pool/pool.hpp>
#include <iostream>
int main()
{
boost::pool<> pool_a(1024*128);
boost::pool<> pool_b(1024*128,5*1024*1024);
auto get_mem_blk = [](boost::pool<>& pool)
{
char* ptr = (char*)pool.ordered_malloc();
pool.ordered_free(ptr);
//memset(ptr,128 * 1024);
};
get_mem_blk(pool_a); //works well
std::cout << "pass first test" << std::endl;
get_mem_blk(pool_b); //segment fault!
std::cout << "pass second test" << std::endl;
}
输出如下：
pass first test
bash: line 7: 8617 Segmentation fault (core dumped) ./a.out
解决方法
只需添加 -fsanitize=address,undefined 即可显示：
==26122==ERROR: AddressSanitizer: allocator is out of memory trying to allocate 0xa000000010 bytes
#0 0x7fe4dd7d3b3f in operator new[](unsigned long,std::nothrow_t const&) (/usr/lib/x86_64-linux-gnu/libasan.so.6+0xb4b3f)
#1 0x5577f383c5b8 in boost::default_user_allocator_new_delete::malloc(unsigned long) /home/sehe/custom/boost_1_76_0/boost/pool/pool.hpp:97
#2 0x5577f383c5b8 in boost::pool<boost::default_user_allocator_new_delete>::ordered_malloc_need_resize() /home/sehe/custom/boost_1_76_0/boost/pool/pool.hpp:733
==26122==HINT: if you don't care about these errors you may set allocator_may_return_null=1
SUMMARY: AddressSanitizer: out-of-memory (/usr/lib/x86_64-linux-gnu/libasan.so.6+0xb4b3f) in operator new[](unsigned long,std::nothrow_t const&)
==26122==ABORTING
问题似乎是 next_size 乘以分区大小。实际上，默认值是“仅”32。您可能指的是您获得的行为
boost::pool<> pool_b(1024 * 128,5 * 8);
或类似的。