From bd8cf2ada19dd071ee1e70d19331c6903f9fa943 Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Thu, 16 Jul 2015 01:54:28 -0400
Subject: [PATCH] win pipe: missing conditional check on
 uv_pipe_zero_readfile_thread_proc

fixes a race condition where if uv_read_stop was called shortly after uv_read_start or a successful read and before the uv_pipe_zero_readfile_thread_proc thread started, that thread would call the blocking ReadFile call after the HANDLE_READING flag had already been cleared
---
 src/win/pipe.c | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/src/win/pipe.c b/src/win/pipe.c
index 6503855127e..8ee458c5198 100644
--- a/src/win/pipe.c
+++ b/src/win/pipe.c
@@ -1089,26 +1089,30 @@ static DWORD WINAPI uv_pipe_zero_readfile_thread_proc(void* parameter) {
     uv_mutex_unlock(m);
   }
 restart_readfile:
-  result = ReadFile(handle->handle,
-                    &uv_zero_,
-                    0,
-                    &bytes,
-                    NULL);
-  if (!result) {
-      err = GetLastError();
-      if (err == ERROR_OPERATION_ABORTED && m) {
-          if (handle->flags & UV_HANDLE_READING) {
-            /* just a brief break to do something else */
-            handle->readfile_thread = NULL;
-            /* resume after it is finished */
-            uv_mutex_lock(m);
-            handle->readfile_thread = hThread;
-            uv_mutex_unlock(m);
-            goto restart_readfile;
-         } else {
-            result = 1; /* successfully stopped reading */
-         }
+  if (handle->flags & UV_HANDLE_READING) {
+      result = ReadFile(handle->handle,
+                        &uv_zero_,
+                        0,
+                        &bytes,
+                        NULL);
+      if (!result) {
+          err = GetLastError();
+          if (err == ERROR_OPERATION_ABORTED && m) {
+              if (handle->flags & UV_HANDLE_READING) {
+                /* just a brief break to do something else */
+                handle->readfile_thread = NULL;
+                /* resume after it is finished */
+                uv_mutex_lock(m);
+                handle->readfile_thread = hThread;
+                uv_mutex_unlock(m);
+                goto restart_readfile;
+             } else {
+                result = 1; /* successfully stopped reading */
+             }
+          }
       }
+  } else {
+      result = 1; /* successfully aborted read before it even started */
   }
   if (hThread) {
     assert(hThread == handle->readfile_thread);