Consider the following scenario: 1. A freeze notification is delivered to thread 1. 2. The process becomes frozen or unfrozen. 3. The message for step 2 is delivered to thread 2 and ignored because there is already a pending notification from step 1. 4. Thread 1 acknowledges the notification from step 1. In this case, step 4 should ensure that the message ignored in step 3 is resent as it can now be delivered. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Carlos Llamas <cmllamas@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>