Merge pull request #4599 from evanphx/evanphx/b-logs-hang

libcontainer: Prevent startup hang when CloseExecFrom errors

Author: AkihiroSuda

libcontainer/container_linux.go

@@ -324,16 +324,6 @@ func (c *Container) start(process *Process) (retErr error) {
 	defer process.closeClonedExes()
 
 	logsDone := parent.forwardChildLogs()
-	if logsDone != nil {
-		defer func() {
-			// Wait for log forwarder to finish. This depends on
-			// runc init closing the _LIBCONTAINER_LOGPIPE log fd.
-			err := <-logsDone
-			if err != nil && retErr == nil {
-				retErr = fmt.Errorf("unable to forward init logs: %w", err)
-			}
-		}()
-	}
 
 	// Before starting "runc init", mark all non-stdio open files as O_CLOEXEC
 	// to make sure we don't leak any files into "runc init". Any files to be
@@ -348,6 +338,17 @@ func (c *Container) start(process *Process) (retErr error) {
 		return fmt.Errorf("unable to start container process: %w", err)
 	}
 
+	if logsDone != nil {
+		defer func() {
+			// Wait for log forwarder to finish. This depends on
+			// runc init closing the _LIBCONTAINER_LOGPIPE log fd.
+			err := <-logsDone
+			if err != nil && retErr == nil {
+				retErr = fmt.Errorf("unable to forward init logs: %w", err)
+			}
+		}()
+	}
+
 	if process.Init {
 		c.fifo.Close()
 		if c.config.HasHook(configs.Poststart) {