SERVER-21108 don't call cancel on destroyed timers

2 files changed, 14 insertions, 9 deletions

diff --git a/src/mongo/executor/connection_pool.cpp b/src/mongo/executor/connection_pool.cpp
index 169caef2e38..a6b39841826 100644
--- a/src/mongo/executor/connection_pool.cpp
+++ b/src/mongo/executor/connection_pool.cpp
@@ -460,8 +460,7 @@ void ConnectionPool::SpecificPool::fulfillRequests(stdx::unique_lock<stdx::mutex
         conn->cancelTimeout();
 
         if (!conn->isHealthy()) {
-            log() << "dropping unhealthy pooled connection to " << conn->getHostAndPort().host()
-                  << ":" << conn->getHostAndPort().port();
+            log() << "dropping unhealthy pooled connection to " << conn->getHostAndPort();
 
             if (_readyPool.empty()) {
                 log() << "after drop, pool was empty, going to spawn some connections";
diff --git a/src/mongo/executor/connection_pool_asio.cpp b/src/mongo/executor/connection_pool_asio.cpp
index 6a9065faef3..2b475016057 100644
--- a/src/mongo/executor/connection_pool_asio.cpp
+++ b/src/mongo/executor/connection_pool_asio.cpp
@@ -48,7 +48,8 @@ ASIOTimer::ASIOTimer(asio::io_service::strand* strand)
       _callbackSharedState(std::make_shared<CallbackSharedState>()) {}
 
 ASIOTimer::~ASIOTimer() {
-    cancelTimeout();
+    stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
+    ++_callbackSharedState->id;
 }
 
 void ASIOTimer::setTimeout(Milliseconds timeout, TimeoutCallback cb) {
@@ -90,12 +91,17 @@ void ASIOTimer::setTimeout(Milliseconds timeout, TimeoutCallback cb) {
 }
 
 void ASIOTimer::cancelTimeout() {
-    _strand->dispatch([this] {
-        {
-            stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
-            _callbackSharedState->id++;
-        }
-
+    decltype(_callbackSharedState) sharedState;
+    decltype(_callbackSharedState->id) id;
+    {
+        stdx::lock_guard<stdx::mutex> lk(_callbackSharedState->mutex);
+        id = ++_callbackSharedState->id;
+        sharedState = _callbackSharedState;
+    }
+    _strand->dispatch([this, id, sharedState] {
+        stdx::lock_guard<stdx::mutex> lk(sharedState->mutex);
+        if (sharedState->id != id)
+            return;
         _impl.cancel();
     });
 }