3 files changed, 21 insertions, 4 deletions

diff --git a/runtime/jdwp/jdwp.h b/runtime/jdwp/jdwp.h
index e45cb6e..1ec795f 100644
--- a/runtime/jdwp/jdwp.h
+++ b/runtime/jdwp/jdwp.h
@@ -154,8 +154,9 @@ struct JdwpState {
    * release it in the "clear" call.
    */
   // ObjectId GetWaitForEventThread();
-  void SetWaitForEventThread(ObjectId threadId);
-  void ClearWaitForEventThread();
+  void SetWaitForEventThread(ObjectId threadId)
+      LOCKS_EXCLUDED(event_thread_lock_, process_request_lock_);
+  void ClearWaitForEventThread() LOCKS_EXCLUDED(event_thread_lock);
 
   /*
    * These notify the debug code that something interesting has happened.  This
@@ -346,7 +347,7 @@ struct JdwpState {
 
   // Used to synchronize request processing and event sending (to avoid sending an event before
   // sending the reply of a command being processed).
-  Mutex process_request_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
+  Mutex process_request_lock_ ACQUIRED_AFTER(event_thread_lock_);
   ConditionVariable process_request_cond_ GUARDED_BY(process_request_lock_);
   bool processing_request_ GUARDED_BY(process_request_lock_);
 
diff --git a/runtime/jdwp/jdwp_handler.cc b/runtime/jdwp/jdwp_handler.cc
index 0ff78d0..4b170ba 100644
--- a/runtime/jdwp/jdwp_handler.cc
+++ b/runtime/jdwp/jdwp_handler.cc
@@ -1685,6 +1685,12 @@ void JdwpState::ProcessRequest(Request& request, ExpandBuf* pReply) {
   SetWaitForEventThread(0);
 
   /*
+   * We do not want events to be sent while we process a request. Indicate the JDWP thread starts
+   * to process a request so other threads wait for it to finish before sending an event.
+   */
+  StartProcessingRequest();
+
+  /*
    * Tell the VM that we're running and shouldn't be interrupted by GC.
    * Do this after anything that can stall indefinitely.
    */
@@ -1779,9 +1785,15 @@ void JdwpState::WaitForProcessingRequest() {
   Thread* self = Thread::Current();
   CHECK_NE(self, GetDebugThread()) << "Events should not be posted by debug thread";
   MutexLock mu(self, process_request_lock_);
+  bool waited = false;
   while (processing_request_) {
+    VLOG(jdwp) << StringPrintf("wait for processing request");
+    waited = true;
     process_request_cond_.Wait(self);
   }
+  if (waited) {
+    VLOG(jdwp) << StringPrintf("finished waiting for processing request");
+  }
   CHECK_EQ(processing_request_, false);
 }
 
diff --git a/runtime/jdwp/jdwp_main.cc b/runtime/jdwp/jdwp_main.cc
index ba49c45..500585d 100644
--- a/runtime/jdwp/jdwp_main.cc
+++ b/runtime/jdwp/jdwp_main.cc
@@ -386,10 +386,14 @@ bool JdwpState::HandlePacket() {
   JdwpNetStateBase* netStateBase = reinterpret_cast<JdwpNetStateBase*>(netState);
   JDWP::Request request(netStateBase->input_buffer_, netStateBase->input_count_);
 
-  StartProcessingRequest();
   ExpandBuf* pReply = expandBufAlloc();
   ProcessRequest(request, pReply);
   ssize_t cc = netStateBase->WritePacket(pReply);
+
+  /*
+   * We processed this request and sent its reply. Notify other threads waiting for us they can now
+   * send events.
+   */
   EndProcessingRequest();
 
   if (cc != (ssize_t) expandBufGetLength(pReply)) {