From 831940a73194fa5d24419fa3f0a08e1ce3a41958 Mon Sep 17 00:00:00 2001
From: Muxi Yan <mxyan@google.com>
Date: Tue, 24 Oct 2017 11:05:51 -0700
Subject: [PATCH] Fix some tsan problems in gRPC ObjC

---
 src/objective-c/GRPCClient/GRPCCall.m | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index d6c3a3c165a..f1f7b5d08d2 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -244,9 +244,12 @@ static NSString * const kBearerPrefix = @"Bearer ";
 // method.
 // TODO(jcanizales): Rename to readResponseIfNotPaused.
 - (void)startNextRead {
-  if (self.state == GRXWriterStatePaused) {
-    return;
+  @synchronized(self) {
+    if (self.state == GRXWriterStatePaused) {
+      return;
+    }
   }
+  
   __weak GRPCCall *weakSelf = self;
   __weak GRXConcurrentWriteable *weakWriteable = _responseWriteable;