When running on Xen, it's possible that a suspend request to the hypervisor
fails(return from HYPERVISOR_suspend different than 0), such as when VM dirty pages are faster than the rate of copying. This means that the suspend hasn't succeed, and the resume procedure needs to properly handle this case.
The patch to fix this bug refers to:
These two patches also need to apply to improve migration.
(In reply to Ouyang Zhaowei from comment #1)