kata-agent RemoveContainer timeout buggy?

9 Nov 2018

      It looks like the goroutine will be left running when kata-agent
RemoveContainer() returns after a timeout.  In addition, the sandbox
lock is no longer held so any actions taken by the goroutine could cause
problems.

Am I understanding the code correctly?

func (a *agentGRPC) RemoveContainer(ctx context.Context, req *pb.RemoveContainerRequest) (*gpb.Empty, error) {
	...

        timeout := int(req.Timeout)

        a.sandbox.Lock()
        defer a.sandbox.Unlock()

        if timeout == 0 {
		...
        } else {
                done := make(chan error)
                go func() {
                        if err := ctr.removeContainer(); err != nil {
                                done <- err
                                close(done)
                                return
                        }

                        //Find the sandbox storage used by this container
                        for _, path := range ctr.mounts {
                                if _, ok := a.sandbox.storages[path]; ok {
                                        if err := a.sandbox.unsetAndRemoveSandboxStorage(path); err != nil {
                                                done <- err
                                                close(done)
                                                return
                                        }
                                }
                        }
                        close(done)
                }()

                select {
                case err := <-done:
                        if err != nil {
                                return emptyResp, err
                        }
                case <-time.After(time.Duration(req.Timeout) * time.Second):
                        return emptyResp, grpcStatus.Errorf(codes.DeadlineExceeded, "Timeout reached after %ds", timeout)

Stefan

Stefan Hajnoczi

Tao Peng

Stefan Hajnoczi

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