SF: Fix an EventThread deadlock

EventThread::removeDisplayEventConnection tried to acquire the mutex,
however the caller (eventThread::threadMain()) already had it.

The fix was to not acquire the mutex, since threadMain() was the only
caller.

Bug: 73256320
Test: Can toggle "Show taps" from dev options without lockup.
Change-Id: I855b19b3d0ac9e0ea05604cc7b077f4a5030a00b

2 files changed, 3 insertions, 4 deletions

diff --git a/services/surfaceflinger/EventThread.cpp b/services/surfaceflinger/EventThread.cpp
index 90aab506c8..1f4f5a53f4 100644
--- a/services/surfaceflinger/EventThread.cpp
+++ b/services/surfaceflinger/EventThread.cpp
@@ -100,8 +100,7 @@ status_t EventThread::registerDisplayEventConnection(
     return NO_ERROR;
 }
 
-void EventThread::removeDisplayEventConnection(const wp<EventThread::Connection>& connection) {
-    std::lock_guard<std::mutex> lock(mMutex);
+void EventThread::removeDisplayEventConnectionLocked(const wp<EventThread::Connection>& connection) {
     mDisplayEventConnections.remove(connection);
 }
 
@@ -195,7 +194,7 @@ void EventThread::threadMain() NO_THREAD_SAFETY_ANALYSIS {
                 // handle any other error on the pipe as fatal. the only
                 // reasonable thing to do is to clean-up this connection.
                 // The most common error we'll get here is -EPIPE.
-                removeDisplayEventConnection(signalConnections[i]);
+                removeDisplayEventConnectionLocked(signalConnections[i]);
             }
         }
     }
diff --git a/services/surfaceflinger/EventThread.h b/services/surfaceflinger/EventThread.h
index 708806a22d..97f0a359e2 100644
--- a/services/surfaceflinger/EventThread.h
+++ b/services/surfaceflinger/EventThread.h
@@ -129,7 +129,7 @@ private:
                                                            DisplayEventReceiver::Event* event)
             REQUIRES(mMutex);
 
-    void removeDisplayEventConnection(const wp<Connection>& connection);
+    void removeDisplayEventConnectionLocked(const wp<Connection>& connection) REQUIRES(mMutex);
     void enableVSyncLocked() REQUIRES(mMutex);
     void disableVSyncLocked() REQUIRES(mMutex);