when i upgrade my rb3011 to 6.42.10(long-term)
after 5 days the cpu usage get 100%
after i reboot it .it is the same
when i downgrade to 6.42.9
everything is ok
why?
what did cpu profiler tell you? were was that 100% load coming from?
network and firewall
And so starts the chaise 
. External source (under “attack”) or internal (ex broadcast storm or loop in network)?
yes
i check it
but it is not ,everything is ok
i have another router rb931 ,it has the same problem ,i am so confused ,maybe some packets cause it ,6.42.9 is fine.