[
https://issues.apache.org/jira/browse/THRIFT-3768?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15236340#comment-15236340
]
ASF GitHub Bot commented on THRIFT-3768:
----------------------------------------
Github user tpcwang commented on a diff in the pull request:
https://github.com/apache/thrift/pull/980#discussion_r59305327
--- Diff: lib/cpp/src/thrift/server/TThreadedServer.cpp ---
@@ -90,31 +95,71 @@ TThreadedServer::~TThreadedServer() {
}
void TThreadedServer::serve() {
+ threadFactory_->setDetached(false);
TServerFramework::serve();
- // Drain all clients - no more will arrive
- try {
- Synchronized s(clientsMonitor_);
- while (getConcurrentClientCount() > 0) {
- clientsMonitor_.wait();
- }
- } catch (TException& tx) {
- string errStr = string("TThreadedServer: Exception joining workers: ")
+ tx.what();
- GlobalOutput(errStr.c_str());
+ // Ensure post-condition of no active clients
+ Synchronized s(clientMonitor_);
+ while (!activeClientMap_.empty()) {
+ clientMonitor_.wait();
+ }
+
+ drainDeadClients();
+}
+
+void TThreadedServer::drainDeadClients() {
+ // we're in a monitor here
+ while (!deadClientMap_.empty()) {
+ ClientMap::iterator it = deadClientMap_.begin();
+ it->second->join();
+ deadClientMap_.erase(it);
}
}
void TThreadedServer::onClientConnected(const
shared_ptr<TConnectedClient>& pClient) {
- threadFactory_->newThread(pClient)->start();
+ Synchronized sync(clientMonitor_);
+ drainDeadClients();
--- End diff --
What do you think about draining in onClientDisconnected instead of
onClientConnected (note to take care of draining before adding the thread that
initiated onClientDisconnected to the list of dead clients)? I think it might
be better to make onClientConnected as fast as possible because the serve
thread is the caller?
> TThreadedServer may crash if it is destroyed immediately after it returns
> from serve(); TThreadedServer disconnects clients when they connec
> --------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: THRIFT-3768
> URL: https://issues.apache.org/jira/browse/THRIFT-3768
> Project: Thrift
> Issue Type: Bug
> Components: C++ - Library
> Affects Versions: 0.9.3
> Reporter: Ted Wang
> Assignee: James E. King, III
> Priority: Minor
>
> Here's a sequence that shows the race:
> Thread-1 (Users of TThreadedServer): Calls TThreadedServer::stop(), which
> calls interruptChildren and initiates the tearing down of client connections.
> Thread-2: In TServerFramework::serve(), broke out of accept, and now blocks
> in TThreadedServer::serve() waiting to drain all the clients.
> Thread-3 (The connected client thread created by TThreadedServer): In
> disposeConnectedClient, running because the server is shutting down and the
> shared_ptr specified this function to be the cleanup function for the client.
> This thread just returned from onClientDisconnected and now context switches.
> Thread-2: TThreadedServer::serve() is notified that all of the clients have
> disconnected and completes.
> Thread-1: Joins on Thread-2 and destroys the server object because it is done.
> Thread-3: Finally gets a chance to run, but now encounters undefined behavior
> because it is still executing a member function of an object that has been
> destroyed.
> You can force this race in action if you put sleep(1) before
> onClientDisconnected() in disposeConnectedClient
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
