Description

The "PPE Errors lmem data error" message reports a transient hardware issue.

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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Symptoms

When a "PPE Errors lmem data error" event occurs, a message similar to the following is reported:

Jan 19 19:17:26 router0 fpc0 LUCHIP(2) PPE_0 Errors lmem data error 0x00000c91
Jan 19 19:17:26 router0 fpc0 PPE PPE HW Fault Trap:  Count 1, PC 2dd, 0x02dd:  flow_export_recompute_udp_checksum_for_ipv6


Indications:

  • These memory parity errors will be automatically corrected.

  • Hardware PPE traps would be seen

  • HW Fault Trap: Count #; The amount of traffic drop can be found in the ‘count’ of the HW fault trap message

  • Traffic loss or permanent impact on packet forwarding might be seen if errors are seen continuously. 
  • PFE disable action is also expected in most cases.


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Solution

This is a transient memory parity error which may be service impacting. Repeated errors would disable the affecting zone and report a syslog event like the following:

LMEM errors require LUCHIP(2) PPE 12 Zone 2 disable

If there is a permanent impact on packet forwarding, it will be accompanied by one of the following events:

 

PR1152026 ,  PR1082932  and PR1033660 fixed lmem data error handling scenarios. 

{DIDYOUKNOWSERVICENOWTOKEN.EN_US}

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 "PPE Errors lmem data error" message. Frequently, these events help identify the cause.


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

Tip: When looking at an event in the logs, it is important to focus on the first error message in a collection of syslog messages. The first error message is usually the cause of all the follow-on error messages. The follow-on collateral damage error messages can be ignored.
 

Modification History

2019-10-14: Article reviewed for accuracy; no changes required.

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