[Pkg-net-snmp-devel] Bug#510495: default install of snmpd leaks memory when VLAN interfaces present

[Dave Johnson]

Package: snmpd
Version: 5.2.3-7etch4
Severity: important


The default etch install of snmpd with default config will leak memory if there is 1 or more VLAN ethernet interfaces on the system.

This appears to be a regression between sarge and etch.

After some investigation I've found:

* leak occurs every 60 seconds
* leak occurs at a rate of 1094KB/day _per_ VLAN interface
* rate of leak is directly proportional to the number of VLAN interfaces
* leak occurs even if no snmp activity is happening (get, set, get next, trap, etc..)
* the VLAN interface must have an IPv4 address assigned
* the VLAN interface can be either UP or DOWN
* the name of the VLAN interface doesn't matter

How to recreate:

apt-get install vlan
add to /etc/network/interfaces:

> iface eth0.100 inet static
>     address 10.2.100.1
>     netmask 255.255.255.0
>     broadcast 10.2.100.255

ifup eth0.100
watch snmpd grow...


start of test:
  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  snmp      1886  0.0  0.7   6784  3860 ?        S    22:06   0:00 /usr/sbin/snmpd
after 10 hours:
  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  snmp      1886  0.0  0.8   7300  4316 ?        S    Jan01   0:00 /usr/sbin/snmpd


To amplify the effect, configure 100 VLANs instead of just 1

100 vlans configured:
start of test:
  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  snmp      4694  0.0  0.8   7184  4188 ?        S    09:16   0:00 /usr/sbin/snmpd
after 20 minutes:
  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  snmp      4694  0.0  1.1   8732  5720 ?        S    09:16   0:00 /usr/sbin/snmpd


-- System Information:
Debian Release: 4.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-6-686
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Versions of packages snmpd depends on:
ii  adduser                3.102             Add and remove users and groups
ii  debconf                1.5.11etch2       Debian configuration management sy
ii  libc6                  2.3.6.ds1-13etch8 GNU C Library: Shared libraries
ii  libsensors3            1:2.10.1-3        library to read temperature/voltag
ii  libsnmp9               5.2.3-7etch4      NET SNMP (Simple Network Managemen
ii  libwrap0               7.6.dbs-13        Wietse Venema's TCP wrappers libra

snmpd recommends no packages.

-- debconf information:
  snmpd/upgradefrom521:
  snmpd/upgradefrom36: