ControllerInterface: Fix deadlock when Wii Remote disconnects

In UpdateInput, lock m_devices_population_mutex before m_devices_mutex
to be consistent with other ControllerInterface functions. Normally the
former lock isn't needed in UpdateInput, but when a Wii Remote
disconnects it calls RemoveDevice which results in the mutexes being
locked in the wrong order.

1 files changed, 8 insertions, 0 deletions

diff --git a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
index 6a6affd478..f9c4aa5bc0 100644
--- a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
@@ -372,6 +372,14 @@ void ControllerInterface::UpdateInput()
 
   // TODO: if we are an emulation input channel, we should probably always lock
   // Prefer outdated values over blocking UI or CPU thread (avoids short but noticeable frame drop)
+
+  // Lock this first to avoid deadlock with m_devices_mutex in certain cases (such as a Wii Remote
+  // getting disconnected)
+  if (!m_devices_population_mutex.try_lock())
+    return;
+
+  std::lock_guard population_lock(m_devices_population_mutex, std::adopt_lock);
+
   if (!m_devices_mutex.try_lock())
     return;