possible snmpd bug

[George Bonser <grep@shorelink.com>]

Configuration:

snmpd on router running zebra with full BGP internet routes.
Zebra routing table is pretty large:

L3-Wan-A:~# route -n | wc -l
  75242


snmpwalk will get to the point where it starts to hit the routing table
and then times out. Top shows CPU at 100% for several minutes while it
eats memory to about 50Meg then sits there like this:

  PID USER     PRI  NI  SIZE  RSS SHARE STAT  LIB %CPU %MEM   TIME COMMAND
14567 root       0   0 50460  49M   756 S       0  0.0 19.5   8:33 snmpd

What I SUSPECT is happening is that rather than walk through the routing
table spitting out each route as it finds it, it attempts to gather up all
routes and then spit them out all at once. Trouble is the client times out
before snmpd can give it any output. I also SUSPECT (but do not know) that
snmpd is now trying to give the information to a client that has gone
away. It has been several minutes now and it still has not given back the
49MB of RAM.

Killing and restarting snmpd releases the memory.