Wait for the reply from the 'D' detach packet before tearing down the debugger. Avoids a race

condition where we could end up killing debugserver (and thus the target) before it had a chance
to detach.
Also fix debugserver to send the OK AFTER it detaches to avoid the same race condition.

<rdar://problem/16202713>

llvm-svn: 205043

2 files changed, 14 insertions, 4 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 9b9de22808c..e27186ff86c 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1756,14 +1756,16 @@ GDBRemoteCommunicationClient::Detach (bool keep_stopped)
         }
         else
         {
-            PacketResult packet_result = SendPacket ("D1", 2);
+            StringExtractorGDBRemote response;
+            PacketResult packet_result = SendPacketAndWaitForResponse ("D1", 1, response, false);
             if (packet_result != PacketResult::Success)
                 error.SetErrorString ("Sending extended disconnect packet failed.");
         }
     }
     else
     {
-        PacketResult packet_result = SendPacket ("D", 1);
+        StringExtractorGDBRemote response;
+        PacketResult packet_result = SendPacketAndWaitForResponse ("D", 1, response, false);
         if (packet_result != PacketResult::Success)
             error.SetErrorString ("Sending disconnect packet failed.");
     }
diff --git a/lldb/tools/debugserver/source/RNBRemote.cpp b/lldb/tools/debugserver/source/RNBRemote.cpp
index 2d8b36688e4..a74fdf1e189 100644
--- a/lldb/tools/debugserver/source/RNBRemote.cpp
+++ b/lldb/tools/debugserver/source/RNBRemote.cpp
@@ -3605,9 +3605,17 @@ RNBRemote::HandlePacket_C (const char *p)
 rnb_err_t
 RNBRemote::HandlePacket_D (const char *p)
 {
-    SendPacket ("OK");
     if (m_ctx.HasValidProcessID())
-        DNBProcessDetach(m_ctx.ProcessID());
+    {
+        if (DNBProcessDetach(m_ctx.ProcessID()))
+            SendPacket ("OK");
+        else
+            SendPacket ("E");
+    }
+    else
+    {
+        SendPacket ("E");
+    }
     return rnb_success;
 }