This article explains the scenario where FPC reboots due to Data cache push parity error.

The reason for the FPC restart is due to parity errors reported at the CPU cache memory. Data cache push parity error is a hardware failure and requires a FPC replacement. These parity errors may result in an FPC core and reboot of the FPC.

Example of the "Data cache push parity error":

System Exception: Vector/Code 0x00200, Signal 11
Event occurred at: Jul 30 07:51:53.109719

Juniper Embedded Microkernel Version 18.2R3-S7.4
Built by builder on 2021-01-26 05:51:24 UTC
Copyright (C) 1998-2021, Juniper Networks, Inc.
All rights reserved.
Reason string: "Machine Check"
Context: Thread (PPM Data thread)
Machine Check address reg 0x43a2c6a0, Syndrome 0x20000000
Data cache push parity error

An FPC core will also be generated while checking under "show system core-dump".

-rw-r--r-- 1 root wheel  99881189 Aug 14 14:21 /var/crash/core-MX_xxxxx.gz.core.0 <<<<<<<<

Check the NVRAM output by running the following from the FPC shell

>start shell pfe network fpc#      << replace the '#' with the FPC number which is problematic. 
show nvram
Once the "Data cache push parity error" is observed, please perform a hardware replacement of the FPC or request for RMA from Juniper.

20-DEC-2023 - KB symptoms and solution updated.