This article explains why a Major Error alarm with the error message "FPC Major Errors - XQSS_CMERROR_CPQW_ERR_INT_FSET_FL_OVERFLOW_ERR" might be seen on MX Series routers and what should be done to resolve the error.

When a "XQSS CPQW FL overflow" event occurs, a message similar to the following is reported:

May 16 16:33:03.702 2024 Router-re0 fpc5 CMError: /fpc/5/pfe/0/cm/0/XQSS(0)/0/XQSS_CMERROR_CPQW_ERR_INT_FSET_FL_OVERFLOW_ERR (0x2300df), scope: pfe, category: functional, severity: major, module: XQSS(0), type: XQSS CPQW FL overflow

Indications:
 

• Traffic impact or permanent impact on traffic forwarding might be seen if errors are seen repeatedly

• Alarm will be raised

The "XQSS CPQW FL overflow" message reports an internal software state issue in the EACHIP related to pointer management.

The reported error 'XQSS_CMERROR_CPQW_ERR_INT_FSET_FL_OVERFLOW_ERR' means that the CPQW Freelist Manager has received more free pointers that the size of the free list itself. 

This error indicates a functional issue impacting the PFE. This could mean that PFE is already in an unstable/wedged state.

This is a memory related issue in the CPQW block, it is not possible to recover from these errors and PFE disable is required to reset things afresh. 

Perform these steps to determine the cause and resolve the problem (if any).

Collect the show command output.

• show log messages
• show log chassisd
• start shell pfe networl
• show nvram
• show syslog messages

Analyze the show command output.

• In the 'show log messages', review the events that occurred at or just before the appearance of the "XQSS CPQW FL overflow" message. Frequently these events help identify the cause.
• This error will trigger a major error alarm and pfe-disable action will be triggered
• FPC restart during a maintenance window should clear this error
• Contact your technical support representative if this issue is seen repeatedly.