Race condition possibility when MAC move

[marian-pritsak]

Description

• BGP is about to remove the MAC from local FDB, as it was aged out by remote node
• At the same time the same MAC is already learned locally and local event that is raised is MAC_MOVE as old MAC is still programmed locally
• The event is received by SDK background process and relayed to user space process and waits in FD
• BGP sends the remove command and updates local DB and issues a command to SAI to remove the MAC
• User space process receives the MAC_MOVE event and sends it to Sonic
• Sonic receives MAC_MOVE about the mac that doesn’t exist anymore in the SONiC DB

Steps to reproduce the issue:

Describe the results you received:

As a result, SONiC will print an error message in the log "FdbOrch MOVE notification: mac %s is not found in bv_id 0x%"

Describe the results you expected:

This condition should have a grace period for removal of the entries

Output of show version:

(paste your output here)

Output of show techsupport:

(paste your output here or download and attach the file here )

Additional information you deem important (e.g. issue happens only occasionally):

[anshuv-mfst]

Issue triage meeting 5/26/21: Lower priority issue, can be taken up by Nvidia team.

[anshuv-mfst]

@dgsudharsan - FYI