Symptom

ACI leaf may stop learning endpoints after one of the two commands mentioned in the "Conditions" section is performed. The following messages will be seen in /var/log/dme/log/epmc-trace.txt on ACI LEAF when it failed to learn an EP by hitting this issue. [ :epmc_sdk_prog_failure:2557:t] Disabling learning due to limit failure: 0x2 [ :epmc_sdk_prog_failure:2557:t] Disabling learning due to limit failure: 0x22 Example: [2018 May 23 17:12:49.986667956:14480936:epmc_sdk_prog_failure:2557:t] Disabling learning due to limit failure: 0x22

Conditions

This issue can be observed when one of the following two commands were executed under vsh_lc mode on ACI LEAF. module-1# clear platform internal hal counters l2entrydebug module-1# clear platform internal hal counters l3entrydebug These commands are only for internal debug use to clear some counters on HAL(Hardware Abstraction Layer) process. These commands should never be used prior to the fix of this defect.

Workaround

A leaf reboot does fix the issue

Further Problem Description