Setting the system time make the Qt program blocked.

[alps_xing]

I'm using Qt Embedded for linux. I start my Qt application, and then I type command "date" to set the system time. It will often cause my Qt application blocked inside "Qeventdispacher_unix.cpp". I think the Qt lib is not doing well with the system time handling between multi processes.
Do you know if Qt have resolved this problem? If not, any other better way to change the system time outside the Qt application?
Thanks.