Segmentation fault in DNS resolver SetCancelCallback

[jvalenciag]

SIGSEGV (Segmentation fault) when calling connect using localhost in a TCPClient

I0331 15:47:23.219928 12023 tcp_client.cc:44] TCPClient::Connect remote_addr=localhost:9099
I0331 15:47:23.219969 12023 connector.cc:20] Connector::Connector this=0x555555785120 raddr=localhost:9099
I0331 15:47:23.219995 12023 sockets.cc:103] ParseFromIPPort inet_pton(AF_INET 'localhost', ...) rc=0. localhost is not a valid IP address. Maybe it is a hostname.
I0331 15:47:23.220072 12023 connector.cc:47] Try to connect localhost:9099 status=kDisconnected
I0331 15:47:23.220132 12023 inner_pre.cc:63] event_add ev=0x555555783ba0 fd=-1 user_ptr=0x555555786020 tid=140737353916160
I0331 15:47:23.220154 12023 connector.cc:59] The remote address localhost:9099 is a host, try to resolve its IP address.
I0331 15:47:23.220237 12023 dns_resolver.cc:22] DNSResolver::Start tid=140737353916160 this=0x555555784550
I0331 15:47:23.220242 12023 dns_resolver.cc:116] call shared_from_this
I0331 15:47:23.220360 12023 dns_resolver.cc:194] this->use_count=3
I0331 15:47:23.220412 12023 dns_resolver.cc:179] localhost resolved a ip=127.0.0.1

Stack trace

#0  0x000055555555d61d in std::swap<std::_Any_data> (__a=..., __b=...) at /usr/include/c++/6/bits/move.h:191
#1  0x00007ffff7b534ab in std::function<void ()>::swap(std::function<void ()>&) (this=0x7fffffffd830, __x=...) at /usr/include/c++/6/functional:2025
#2  0x00007ffff7b5244d in std::function<void ()>::operator=(std::function<void ()> const&) (this=0x40, __x=...) at /usr/include/c++/6/functional:1940
#3  0x00007ffff7b674cd in evpp::EventWatcher::SetCancelCallback(std::function<void ()> const&) (this=0x0, cb=...) at evpp/libevent_watcher.cc:96
#4  0x00007ffff7b574be in evpp::DNSResolver::ClearTimer (this=0x555555784550) at evpp/dns_resolver.cc:200
#5  0x00007ffff7b571f5 in evpp::DNSResolver::OnResolved (this=0x555555784550, errcode=0, addr=0x555555782b60) at evpp/dns_resolver.cc:182
#6  0x00007ffff7b57422 in evpp::DNSResolver::OnResolved (errcode=0, addr=0x555555782b60, arg=0x555555782910) at evpp/dns_resolver.cc:195
#7  0x00007ffff6ab8ce8 in evdns_getaddrinfo () from /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5
#8  0x00007ffff7b56d3a in evpp::DNSResolver::AsyncDNSResolve (this=0x555555784550) at evpp/dns_resolver.cc:120
#9  0x00007ffff7b5635a in evpp::DNSResolver::<lambda()>::operator()(void) const (__closure=0x7fffffffdbe0) at evpp/dns_resolver.cc:26
#10 0x00007ffff7b57668 in std::_Function_handler<void(), evpp::DNSResolver::Start()::<lambda()> >::_M_invoke(const std::_Any_data &) (__functor=...) at /usr/include/c++/6/functional:1740
#11 0x00007ffff7b5afce in std::function<void ()>::operator()() const (this=0x7fffffffdbe0) at /usr/include/c++/6/functional:2136
#12 0x00007ffff7b5a360 in evpp::EventLoop::RunInLoop(std::function<void ()>&&) (this=0x7fffffffdef0, functor=<unknown type in /usr/local/lib/libevpp.so.0.3, CU 0x3c472, DIE 0x49ae8>) at evpp/event_loop.cc:207
#13 0x00007ffff7b563e2 in evpp::DNSResolver::Start (this=0x555555784550) at evpp/dns_resolver.cc:31
#14 0x00007ffff7b5034d in evpp::Connector::Start (this=0x555555785120) at evpp/connector.cc:66
#15 0x00007ffff7b6c396 in evpp::TCPClient::<lambda()>::operator()(void) const (__closure=0x7fffffffde00) at evpp/tcp_client.cc:49
#16 0x00007ffff7b6d4bc in std::_Function_handler<void(), evpp::TCPClient::Connect()::<lambda()> >::_M_invoke(const std::_Any_data &) (__functor=...) at /usr/include/c++/6/functional:1740
#17 0x00007ffff7b5afce in std::function<void ()>::operator()() const (this=0x7fffffffde00) at /usr/include/c++/6/functional:2136
#18 0x00007ffff7b5a360 in evpp::EventLoop::RunInLoop(std::function<void ()>&&) (this=0x7fffffffdef0, functor=<unknown type in /usr/local/lib/libevpp.so.0.3, CU 0x3c472, DIE 0x49ae8>) at evpp/event_loop.cc:207
#19 0x00007ffff7b6c48e in evpp::TCPClient::Connect (this=0x7fffffffdfe0) at evpp/tcp_client.cc:51
#20 0x000055555555bef1 in main (argc=1, argv=0x7fffffffe1d8) at /home/jvalencia/workspace/cnettests/client.cpp:61

[zieckey]

Please paste the whole code which can produce this issue. Thanks.

[jvalenciag]

Is a simple TCPClient, I am ussing g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005

int main(int argc, char* argv[]) {
    evpp::EventLoop loop;
    evpp::TCPClient client (&loop,"localhost:9099","TestClient");

    client.SetConnectionCallback(&OnConnection);
    client.SetMessageCallback(&OnMessage);
    client.Connect();
    loop.Run();
    return 0;
}

[jvalenciag]

Occurs only when using "localhost"

[zieckey]

OK, I am working on it.

[zieckey]

Please try again using the lastest code.
Thanks for reporting this bug.

[jvalenciag]

Thank you!