A customer has reported encountering the following error message on a PTX router:
**"jprds_alpha_delete() 135: Alpha KHT delete failed."**
root> show version detail no-forwarding
Hostname:ABCD123
Model: ptx10002-60c
PFE-1: fpc0 jprds_alpha_kht_delete() 162: Chash delete failed.
PFE-1: fpc0 jprds_alpha_delete() 135: Alpha KHT delete failed.
PFE-1: fpc0 expr_dfw_flt_inst_change:1241 Failed to create ABC_123 on PFE 0
1. Collect Diagnostic Logs:
- Gather the RSI and logs from the chassis to analyze the issue.
2. Verify Configuration:
- Check the number of prefix lists configured on the router.
3. Collect Shell Outputs:
- Access the shell and execute the following commands to gather necessary data:
start shell
cprod -A fpc0 -c 'show shim jchash'
cprod -A fpc0 -c 'show filter hw kht-cell-utilization'
cprod -A fpc0 -c 'show filter hw filter-block'
cprod -A fpc0 -c 'show filter hw chip-instance 0 alpha -1 kht stats'
cprod -A fpc0 -c 'show filter hw chip-instance 0 info'
cprod -A fpc0 -c 'show filter hw summary'
cprod -A fpc0 -c 'show filter hw chip-instance all info'
- If the customer is unable to collect logs from the affected router, check if the same software version is available in a lab environment for further analysis.
4. Analyze KHT-Cell Utilization:
- Generate and review the KHT-Cell utilization graph to identify issue start time and check for any configuration changes as issue start time.
Root Cause Analysis (RCA):
- As per PR1426539, the root cause is a logic flaw in memory release, which eventually leads to memory corruption and filter malfunctioning.
- The scope of corruption is non-deterministic, and post-symptoms can vary based on the exposure of corruption.
- Certain edge cases may still trigger this corruption, leading to **ADD/DELETE failures**, even with a reduced prefix-list scale.
https://prsearch.juniper.net/problemreport/PR1426539
Recommended Action:
To prevent further issues and eliminate memory corruption, it is highly recommended that the customer apply the available fix version before proceeding with any additional investigations.