[dev.types] all: merge master into dev.typesdev.types

Change-Id: Ia6964cb4e09153c15cc9c5b441373d1b3cb8f757

1 files changed, 15 insertions, 3 deletions

diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index d37b52b13d..b97c4268b5 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -1528,6 +1528,10 @@ func (pconn *persistConn) addTLS(name string, trace *httptrace.ClientTrace) erro
 	return nil
 }
 
+type erringRoundTripper interface {
+	RoundTripErr() error
+}
+
 func (t *Transport) dialConn(ctx context.Context, cm connectMethod) (pconn *persistConn, err error) {
 	pconn = &persistConn{
 		t:             t,
@@ -1694,9 +1698,9 @@ func (t *Transport) dialConn(ctx context.Context, cm connectMethod) (pconn *pers
 	if s := pconn.tlsState; s != nil && s.NegotiatedProtocolIsMutual && s.NegotiatedProtocol != "" {
 		if next, ok := t.TLSNextProto[s.NegotiatedProtocol]; ok {
 			alt := next(cm.targetAddr, pconn.conn.(*tls.Conn))
-			if e, ok := alt.(http2erringRoundTripper); ok {
+			if e, ok := alt.(erringRoundTripper); ok {
 				// pconn.conn was closed by next (http2configureTransport.upgradeFn).
-				return nil, e.err
+				return nil, e.RoundTripErr()
 			}
 			return &persistConn{t: t, cacheKey: pconn.cacheKey, alt: alt}, nil
 		}
@@ -1963,6 +1967,15 @@ func (pc *persistConn) mapRoundTripError(req *transportRequest, startBytesWritte
 		return nil
 	}
 
+	// Wait for the writeLoop goroutine to terminate to avoid data
+	// races on callers who mutate the request on failure.
+	//
+	// When resc in pc.roundTrip and hence rc.ch receives a responseAndError
+	// with a non-nil error it implies that the persistConn is either closed
+	// or closing. Waiting on pc.writeLoopDone is hence safe as all callers
+	// close closech which in turn ensures writeLoop returns.
+	<-pc.writeLoopDone
+
 	// If the request was canceled, that's better than network
 	// failures that were likely the result of tearing down the
 	// connection.
@@ -1988,7 +2001,6 @@ func (pc *persistConn) mapRoundTripError(req *transportRequest, startBytesWritte
 		return err
 	}
 	if pc.isBroken() {
-		<-pc.writeLoopDone
 		if pc.nwrite == startBytesWritten {
 			return nothingWrittenError{err}
 		}