Description

The "DMEM allocation 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 "DMEM allocation memory parity error" event occurs, a message similar to the following is reported:

<Host> <FPC#> XMCHIP(x): MALLOC: DMEM allocation memory parity error
<Host> <FPC#> XMCHIP(x): MALLOC: Two or more DMEM allocation memory parity error

Indications:

  1. Single occurrence of this syslog message not seen with other events indicates a one time hardware error. Multiple continuous occurrences indicates persistent underlying issues.
  2. Traffic impact or PFE permanent packet forwarding issues may happen if errors are seen repeatedly.

 

Solution

The cause is due to a transient parity error detected in internal XMCHIP memory. A software workaround is implemented to throttle the messages in  PR958661 ; with the fix in this PR, the first three occurrences are reported. The error itself can still be seen.
 

 

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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.

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    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 "DMEM allocation memory parity error" message. Frequently these events help identify the cause.

    • No RMA required.
    • Restart the MPC and monitor the errors.
    • Contact your technical support representative if the issue is seen after a FPC restart.
 

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.

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