使用boost syslog和cpp-netlib时出现分段错误

Question

在将boost syslog添加到源代码后，在cpp-netlib库中出现了分段错误。我已经准备了最小的工作代码片段来重现这个问题。

#include <boost/network/protocol/http/client.hpp>
#include <boost/log/utility/setup/file.hpp>
#include <boost/log/sinks/syslog_backend.hpp>

#include <iostream>

using namespace boost::network;
using namespace boost::network::http;

namespace sinks = boost::log::sinks;

int main()
{
    client::request request_("http://www.boost.org/");
    client client_;
    client::response response_ = client_.get(request_);
    std::string body_ = body(response_);
    std::cout << "body: " << body_;
    using syslog_sinkT = sinks::synchronous_sink <sinks::syslog_backend>;
    boost::shared_ptr <sinks::syslog_backend> backend = boost::make_shared <sinks::syslog_backend> ();
    boost::shared_ptr<syslog_sinkT> sink = boost::make_shared <syslog_sinkT> (backend);
}

当最后两行被注释时，段错误消失了，一切正常运作。

gdb堆栈跟踪（大致上，可能会有所不同）：

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xf7c29b40 (LWP 19874)]
0x00000000 in ?? ()
(gdb) where
#0  0x00000000 in ?? ()
#1  0x083c376c in boost::asio::detail::task_io_service_operation::complete (bytes_transferred=260, ec=..., owner=..., 
    this=0xf6900710)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/asio/detail/task_io_service_o$
eration.hpp:38
#2  boost::asio::detail::task_io_service::do_run_one (ec=..., this_thread=..., lock=..., this=<optimized out>)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/asio/detail/impl/task_io_serv$
ce.ipp:372
#3  boost::asio::detail::task_io_service::run (ec=..., this=0x84ea280)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/asio/detail/impl/task_io_serv$
ce.ipp:149
#4  boost::asio::io_service::run (this=0x84e9a94)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/asio/impl/io_service.ipp:59
#5  0x083b5766 in boost::_mfi::mf0<unsigned int, boost::asio::io_service>::operator() (p=<optimized out>, this=<optimized out>)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/bind/mem_fn_template.hpp:49
#6  boost::_bi::list1<boost::_bi::value<boost::asio::io_service*> >::operator()<unsigned int, boost::_mfi::mf0<unsigned int, boost::a$
io::io_service>, boost::_bi::list0> (a=<synthetic pointer>, f=..., this=0x84ea94c)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/bind/bind.hpp:249
#7  boost::_bi::bind_t<unsigned int, boost::_mfi::mf0<unsigned int, boost::asio::io_service>, boost::_bi::list1<boost::_bi::value<boo$
t::asio::io_service*> > >::operator() (this=0x84ea944)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/bind/bind.hpp:1222
#8  boost::detail::thread_data<boost::_bi::bind_t<unsigned int, boost::_mfi::mf0<unsigned int, boost::asio::io_service>, boost::_bi::$
ist1<boost::_bi::value<boost::asio::io_service*> > > >::run (this=0x84ea828)
    at /home/kostidov/prj/third_party-master/boost/boost_1_60_0/__public__/v0/Linux-libc6/include/boost/thread/detail/thread.hpp:116
#9  0x0840a4f8 in boost::(anonymous namespace)::thread_proxy (param=0x84ea828) at libs/thread/src/pthread/thread.cpp:167
#10 0xf7de1f70 in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#11 0xf7d18bee in clone () from /lib/i386-linux-gnu/libc.so.6

在Ubuntu 14.04上，cpp-netlib 0.11.2和boost版本1_58_0和1_60_0都存在问题。Boost、cpp-netlib和我的应用程序都使用-std=c++11进行编译。

注意1：在达到syslog_backend创建之前，cpp-netlib内部就出现了分段错误。只有最后两行的存在能确保重现SIGSEGV。

注意2：仅在syslog_backend下会出现问题。任何其他记录目标（如文件、控制台）都可以正常工作。 我所拥有的最好想法是问题可能在静态变量初始化期间出现在boost内部，但我没有关于这个版本的证据。 有什么建议吗？

- cdovgal

---

无法在Mac OS X上重现，使用boost 1_57_0和Apple LLVM版本7.0.2（clang-700.1.81）。 - cdovgal

Answer 1

似乎我在构建boost和cpp-netlib时使用了太多的编译选项。 我为boost和cpp-netlib准备了新的构建，但这次尽可能少地使用了额外的选项。 现在它可以正常工作了。

编辑：我找到了导致错误的关键。它是BOOST_ASIO_ENABLE_HANDLER_TRACKING，在boost编译期间定义了它，但在cpp-netlib和我的应用程序编译期间没有定义它。

https://svn.boost.org/trac/boost/ticket/11945

- cdovgal