Description

The "DREF memory parity 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 "DREF memory parity error" event occurs, a message similar to the following is reported:
Jan 28 11:05:42 router0 : %PFE-3: fpc2 XMCHIP(1): XMCHIP(1): MALLOC: DREF memory parity error

Indications:

  1. Single occurrence of syslog, not seen with other events, indicates a one time hardware error. Multiple continuous occurrences indicate persistent underlying issues.

  2. Traffic impact or PFE wedge may happen if errors are seen repeatedly.

 

Solution

The cause is due to a parity error in one of the XMCHIP's MALLOC blocks.


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.

    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 "DREF memory parity error" message. Frequently these events help identify the cause.
    No RMA is required.

  3. During a maintenance window, as it will impact transit traffic, try the following:

    • Reset the specific hardware reporting the error. 

      To ‘reset an FPC’, for example on an MX480:
      Run the CLI command ‘ request chassis fpc slot # offline ’,
      Wait 30 seconds.
      Then follow with the CLI command ‘ request chassis fpc slot # online ’.
      For more information on the command see:  request chassis fpc .

    • If the error transcends FPC reset, then swap the FPC with a spare and verify.

  4. If the log messages continue, open a case with your technical support representative to investigate the issue further.

This article is indexed in KB31893 - primary Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] ; Tag XMCHIPTSG.

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.