http: Join worker threads before deleting work queue

This prevents a potential race condition if control flow ends up in
`ShutdownHTTPServer` before the thread gets to `queue->Run()`,
deleting the work queue while workers are still going to use it.

Meant to fix #12362.

Signed-off-by: Wladimir J. van der Laan <laanwj@gmail.com>
This commit is contained in:
Wladimir J. van der Laan 2018-02-06 19:27:13 +01:00
parent 1462bde767
commit b1c2370dde

View file

@ -449,6 +449,7 @@ bool UpdateHTTPServerLogging(bool enable) {
std::thread threadHTTP;
std::future<bool> threadResult;
static std::vector<std::thread> g_thread_http_workers;
bool StartHTTPServer()
{
@ -460,8 +461,7 @@ bool StartHTTPServer()
threadHTTP = std::thread(std::move(task), eventBase, eventHTTP);
for (int i = 0; i < rpcThreads; i++) {
std::thread rpc_worker(HTTPWorkQueueRun, workQueue);
rpc_worker.detach();
g_thread_http_workers.emplace_back(HTTPWorkQueueRun, workQueue);
}
return true;
}
@ -487,6 +487,10 @@ void StopHTTPServer()
if (workQueue) {
LogPrint(BCLog::HTTP, "Waiting for HTTP worker threads to exit\n");
workQueue->WaitExit();
for (auto& thread: g_thread_http_workers) {
thread.join();
}
g_thread_http_workers.clear();
delete workQueue;
workQueue = nullptr;
}