Kill -USR1 Signal To Cm Fills Children To Maximum

Last updated on JUNE 29, 2016

Applies to:

Symptoms

If we pass kill -USR1 signal to CM, it is updating the children count to maximum allowed. After that we are not able to connect to CM.

Steps to re-produce :

1. Open the cm pin.conf and make the following entry
   
   #==================================================================
   # cm_max_connects
   #
   # Specifies the maximum number of client connections to the CM.
   #
   # The parent CM listens on the port for new connections and spawns a
   # child process for each one. Use this entry to limit the maximum number
   # of child CMs that are spawned by a single CM parent process (or thread).
   #==================================================================
   - cm cm_max_connects 100
2. Restart cm
3. Clear cm pinlog
4. Do a kill -USR1 <proc id>
5. See that the nkids is set to 1 in the cm.pinlog
6. Run kill -USR1 to the same proc id again without clearing the logs
7. See that the nkids gets set to 100 (which should not be the case.)
8. Run testnap, the following error can be seen :
   
   ERROR: testnap: PCM_CONNECT():: err 49:PIN_ERR_STREAM_IO, field 0/0:0,
   loc 0:Unknown pin location, errclass 3:PIN_ERRCLASS_SYSTEM_RETRYABLE, rec_id 0, resvd 0

The only option now is to kill the cm since it no longer accepts any connection.

Cause