ser dead but subsys locked
 

I use the same ser.cfg, sometimes ser is running but sometimes cannot and show error message
'ser dead but subsys locked' when i check the status.

What's wrong with it? Is it related to my ser.cfg? Or other settings?

If your system shuts down uncleanly or ser is crashing and not removing its locak file (usually located in /var/lock or /var/lock/subsys or someplace similar) you can see this error. You can always rm the lock file by hand after you've found it. If the program is crashing and leaving lock files it might be a bug in the code. Does the program print out any logging information? Can you run it in some form of debug mode?