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Syslog message: Uninitialized Read Error



Article ID: KB32155 KB Last Updated: 12 Oct 2021Version: 2.0

The "Uninitialized Read Error" message is caused by a transient hardware or software error.

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 - Index of Articles for Troubleshooting PFE ASIC Syslog Events.



When a "Uninitialized Read Error" event occurs messages similar of the following are reported:

Aug 11 08:39:32 router : %PFE-3: fpc5 Uninitialized Read Error @ EDMEM[0x7d1d1bca]


  • No alarm

  • Traffic impact or PFE wedge may be seen if errors occur repeatedly.



This error is caused by a transient hardware or software defect. PR1032958 fixes false positive double-bit ECC error conditions. Access to unintialized memory with predefined patterns are software errors and the rest are hardware errors. LUCHIP, XLCHIP and EACHIP predifined, scrub, pattern is 0x05B6DB6D6DB6DB6.  Therefore, if an uninitialized read error log reports with 0x05B6DB6D6DB6DB6, then this is a software problem.


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

  2. Analyze the show command output.

    In the 'show log messages', review the events that occurred at or just before the appearance of the "Uninitialized Read 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; tag EACHIPTSG XLCHIPTSG 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.


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