Fix crash due to inconsistent state in QLEController during JobDisconnectDevice

This bug was caused by a problem in the patch for QTBUG-55150.

While the termination of an ongoing BTLE connection is being
processed, the QLEController instance is in Connecting state and
the internal socket is still null. If the user triggers a call
to QLEController::disconnectDevice() while the above state is
pending, it crashes due to a call to the socket's close()
function. The time window for this to happen is very small.
It takes the duration of the bluez dbus call to disconnect
a device.

This patch addresses the above crash bug and adds a
bit more debug output to catch similar cases later on.

Task-number: QTBUG-63619
Change-Id: I893990a9ce8ccf55ddbf619fe177379f79dc9ee3
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/bluetooth/bluez/remotedevicemanager.cpp b/src/bluetooth/bluez/remotedevicemanager.cpp
index f63b21e6..5d17d571 100644
--- a/src/bluetooth/bluez/remotedevicemanager.cpp
+++ b/src/bluetooth/bluez/remotedevicemanager.cpp
@@ -106,6 +106,7 @@ void RemoteDeviceManager::prepareNextJob()
     jobQueue.pop_front();
     jobInProgress = false;
 
+    qDebug(QT_BT_BLUEZ) << "RemoteDeviceManager job queue status:" << jobQueue.empty();
     if (jobQueue.empty())
         emit finished();
     else
@@ -163,8 +164,10 @@ void RemoteDeviceManager::disconnectDevice(const QBluetoothAddress &remote)
         }
     }
 
-    if (!jobStarted)
+    if (!jobStarted) {
+        qDebug(QT_BT_BLUEZ) << "RemoteDeviceManager JobDisconnectDevice failed";
         QTimer::singleShot(0, this, [this](){ prepareNextJob(); });
+    }
 }
 
 QT_END_NAMESPACE