Core issue
The error message can look similar to this:
%SCHED-3-THRASHING: Process thrashing on watched [chars]
This means that a process can register to be notified when various events occur in the router. The process has taken and released control of the processor 50 consecutive times, and not all outstanding events were processed. The systems recover, and the functionality of the router is not affected.
When you try to establish SSH session, you can receive Process= "SSH Process", ipl= 4, pid= 36 traceback messages.
This problem is seen only on Cisco IOS Software Release 12.2S and it is child trains. The traceback occurs every time a Secure Shell (SSH) session is established.
This problem is identified in Cisco bug ID CSCin64958.
Resolution
Currently, there is no workaround for this problem.
If the switch or router becomes sluggish, you can try the clear tcp tcb command, which clears all the TCP sessions to the device. The slugglish response should clear within 10 minutes.
This bug is fixed in Cisco IOS Software Release 12.2(25)S and later, which can be downloaded from Cisco Downloads.
