The "HMCIO RX: SFIFO overflow event" messages is caused due to transient FIFO overflow condition to the Hybrid Memory Cube

This is a Troubleshooting Article for a PFE ASIC Syslog Event.
To view other documented syslog events related to XMCHIP, XLCHIP, MQCHIP, LUCHIP, EACHIP, and PECHIP, see KB31893 - Master Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] .

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When a HMCIO RX: SFIFO overflow event detected in Channel event occurs, a message similar to the following is reported:

[Nov 20 09:17:30.955 LOG: Debug] Cmerror: Draining ASIC error message queue
[Nov 20 09:17:30.955 LOG: Debug] cmerror_process_queue: module = HMM:EA[0:0]
[Nov 20 09:17:30.955 LOG: Debug] Cmerror: processing the task op_type 1 for level 1 level_count 5 occur_count 5 clear_count 0 level_threshold 1 level_action 0x4 item errid 2490369 item_threshold 1 item_count 0 item_sub_err_state 0 sub_item errid 0 sub_item_state 0 item_times[Nov 20 09:17:30.955 LOG: Debug] Cmerror: Level 1 count increment 6 occur_count 6 clear_count 0
[Nov 20 09:17:30.955 LOG: Info] Error: /fpc/8/pfe/0/cm/0/HMM:EA[0:0]/0/HMCIO_LANE_RX_SFIFO_OVERFLOW (0x260001), severity: major, module: HMM:EA[0:0] , type: HMCIO_RX_LANE_SFIFO_OVERFLOW
[Nov 20 09:17:30.955 LOG: Debug] Cmerror: Level 1 count 6 (occur_count 6 clear_count 0)crossed threshold 1 action 0x4
[Nov 20 09:17:30.955 LOG: Debug] cmerror_take_action_helper: performing action 4 for level 1 err_id /fpc/8/pfe/0/cm/0/HMM:EA[0:0]/0/HMCIO_LANE_RX_SFIFO_OVERFLOW (0x260001) module id 15
[Nov 20 09:17:30.955 LOG: Err] Cmerror Op Set: HMM:EA[0:0] : EA[0:0]: HMCIO RX: SFIFO overflow event detected in Channel : EA[0:0]-chan-rx0-sc0, Lane 0

Indications:

• Permanent PFE forwarding impact and FPC is getting restarted automatically due to CMERROR severity Fatal
• An alarm will be raised​
• In Junos 17.3R1 and higher, it will perform the 'disable-pfe' action instead of FPC reset

This indicates that the Rx SFIFO before the serdes has detected an overflow condition which is a fatal error condition from which it cannot recover without a restart.

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Perform these steps to determine the cause and resolve the problem (if any).  Continue through each step until the problem is resolved.

1. Collect the show command output.

   {SYSLOGSERVICENOWTOKEN.EN_US}

   Capture the output to a file (in case you have to open a technical support case). To do this, configure each SSH client/terminal emulator to log your session.

   show log messages
show log chassisd
start shell network pfe <fpc#>
show nvram
show syslog messages
exit

2. Analyze the show command output.

   In the 'show log messages', review the events that occurred at or just before the appearance of the "HMCIO RX: SFIFO overflow event" message. Frequently, these events help identify the cause.

• RMA is only required if after the FPC restart and the same error condition occurs again.
• If the FPC is not passing the internal Power on Self Test (POST) and reports "Error initializing PFE asics", hardware replacements need to be initiated.
• In Junos OS 17.3R1 or higher, the default action will be disable-pfe instead of FPC restart, which is changed within PR1186421.
• Contact your technical support representative immediately.

This article is indexed in  KB31893 - Primary Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] ; tag EACHIPTSG

Note: KB Team - All changes to this article must be approved by the AI-Scripts Review team ( [email protected] ) before re-publishing.