Note :- Applicable before 21.4.L4 contrail dropstats code

Reference Jira :- 

CEM-31546

[RCA] :

Dropstats logging is enabled by default, whenever we pass invalid pkt.

During that instance, pkt-type is compared with IP6 however by we were allowing all packet to go through

when unknown packet is recieved ip header is fetched from pkt. As pkt is invalid ip will be pointing to invalid reference deferring to vrouter crashed.

vrouter crash

vrouter call trace

Debug info :

[135566.836921] vrouter: vr_fragment_assemble At line 516

[135566.836922] vrouter: vr_pkt_drop_log_func At line 1566

The permanent solution is to upgrade to 21.4.L4 and higher.

[Workaround]:-

By disabling "Packet Drop logging at dropstats"

Execute the below :-

“sysctl -w net.vrouter.pkt_drop_log_enable=0”

This will help disabling the packet logging to dropstats.