c++多线程操作list,出现偶发异常

[qq_22229525]

c++多线程操作list，在该list.size()=0后，执行list.resize(0);出错了，该异常偶发，大多情况都运行正常……

[smwhotjay]

多线程操作list 记得用临界锁。

[qq_22229525]

有加锁，代码如下

bool get(T &x)
{
m_lock.Lock();
if (m_listCache.size() == 0)
{
m_listCache.resize(0);
m_lock.UnLock();
return false;
}
else
{
x = m_listCache.back();
m_listCache.pop_back();
m_lock.UnLock();
return true;
}
}

core打印的栈如下：
#0 0x000000000063a7d7 in std::_List_const_iterator<CEventInfo>::operator== (
this=0x7f184ac05978, __x=...)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_list.h:252
#1 0x000000000063b991 in std::distance<std::_List_const_iterator<CEventInfo> > (__first=
Traceback (most recent call last):
File "/usr/lib64/../share/gdb/python/libstdcxx/v6/printers.py", line 108, in to_string
return self.val['_M_node'].cast(nodetype).dereference()['_M_data']
RuntimeError: Cannot access memory at address 0x7463616e49707041
, __last=...)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_iterator_base_funcs.h:118
#2 0x000000000063b9db in std::_Rb_tree<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > >, std::_Select1st<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > > >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > > > >::_M_end (this=0x64872e)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:476
#3 0x000000000063ba0b in std::_Rb_tree<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > >, std::_Select1st<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > > >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::list<CEventInfo, std::allocator<CEventInfo> > > > >::_M_root (this=0xb08a)
at /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_tree.h:442
#4 0x000000000064a6c4 in TemplateMutexCatch<CEventInfo>::get (this=0x10c2498, x=...)
at ../../source/monbasic/./MonTools.h:995

[sdghchj]

T是怎么定义的？

[老葱1#]

虽然不知 size(） == 0， 调用 resize(0) 有啥意义， 但不应该出错。 只能怀疑是有其他线程没有加锁保护的情况下写入list。

[一见]

好象不是出在list，用了map?

[一见]

引用 5 楼 一见 的回复:

好象不是出在list，用了map?

确实，看调用栈是嵌套的：std::map<std::string, std::pair<std::string, std::list<CEventINfo> > >

[qq_22229525]

是用了map，我现在另一个程序也出现了类似的问题，map的second是list，然后map的迭代器取出来值是对的，但是接着用list的迭代器取就是错的，然后程序就挂了…

[赵4老师]

多线程需要加锁。

[636f6c696e]

STL都是非线程安全的，所有访问处都需要加锁，而不只是出错的地方

[yshuise]

你设计的get都有问题，是不能把引用传出，这回破坏加锁