Re: unbounded memory use in net-snmp (5.1.2 up to 5.4)

Hi,

Thanks for your prompt answer.

 From your initial response I have to understand that this is not 
normal. I was already thinking that when I found nothing in this mailing 
list about memory leakage.

Therefore, I have some envrionmental or other situation to deal with. I 
just don't get how I could get the same symptoms across all these 
different environments.

1. I will prepare some tests with valgrind.
2. I do not at present actively use snmpd. Although snmpd is running, it 
is not actively used by anything on our systems today. I am just getting 
started with snmpd. What this means is that snmpd is chewing up memory, 
even though is has virtually no requests. The most I have done is the 
occasional snmpwalk. (manually).
2a) At least one of my copies of snmpd is running with a cong file of:
============snmpd conf ============
rocommunity xxxx
================================
2b) Others (esp. version 5.4) are simply running with the default 
snmpd.conf in the distribution.
2c) There may be other programs we are running that may be trying to 
read information from some of these systems (we have some versions of 
various system monitors  running, who  may be polling all they can 
reach), but this is minimal at best.

3) snmptrapd: This is actively used. It receives traps from Colubris 
network devices: heartbeats, user association/disassociation.
Depending on the host, we have somewhere between 20-150 devices sending 
traps. heartbeats are set to intervals of 60 seconds on one system, 150 
on another.
There are essentially no other traps being received. The actual trap 
handling is provided by perl routines. The same perl modules/routines 
are used on both versions of Linux and on Solaris.
On Linux, I run the perl code embedded, (if 5.4), on solaris via a small 
wrapper that feeds the trap through a socket to a trap receiver (running 
the same code as the others).
On one of the Centos systems running 5.4, I turned off the traps (by 
redirecting port 162) and two days later no increase in memory usages 
was found. This is interesting in itself.

4) For transport, we use udp ports 161 & 162 only.

5) Transient interfaces: On some of these systems we had up to 85 pptpd 
connections running. This was a very unstable setup; I don't think that 
net-snmp and large numbers of pptpd sessions cohabited very well. For 
some time, the snmp traps were going through the pptp links. This is no 
longer the case. We had many problems with the systems going into load 
averages of 85 for  a short while (20-30 minutes or so)  on a regular  
basis  when  we had a large number of pptp connections running along 
with snmptrapd.

Further information:

net-snmp running on Centos was compiled with gcc:
     [root@wifi-web install]# gcc -v
     Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs
     Configured with: ../configure --prefix=/usr --mandir=/usr/share/man 
--infodir=/usr/share/info --enable-shared --enable-threads=posix 
--disable-checking --with-system-zlib     --enable-__cxa_atexit 
--disable-libunwind-exceptions --enable-java-awt=gtk 
--host=i386-redhat-linux
     Thread model: posix
     gcc version 3.4.6 20060404 (Red Hat 3.4.6-3)
     [root@wifi-web install]#

net-snmp on solaris was compiled with gcc:
     intello@wifi-rad1% gcc -v
     Reading specs from /usr/sfw/lib/gcc/sparc-sun-solaris2.10/3.4.3/specs
     Configured with: 
/gates/sfw10/builds/sfw10-gate/usr/src/cmd/gcc/gcc-3.4.3/configure 
--prefix=/usr/sfw --with-as=/usr/sfw/bin/gas --with-gnu-as 
--with-ld=/usr/ccs/bin/ld --without-gnu-ld --enable-languages=c,c++ 
--enable-shared
     Thread model: posix
     gcc version 3.4.3 (csl-sol210-3_4-branch+sol_rpath)
     intello@wifi-rad1%

net-snmp on RH8 (kernel 2.4.31):
     [root@ihdev2 root]# gcc -v
     Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2/specs
     Configured with: ../configure --prefix=/usr --mandir=/usr/share/man 
--infodir=/usr/share/info --enable-shared --enable-threads=posix 
--disable-checking --host=i386-redhat-linux --with-system-zlib 
--enable-__cxa_atexit
     Thread model: posix
     gcc version 3.2 20020903 (Red Hat Linux 8.0 3.2-7)
     [root@ihdev2 root]#

Is there anything particular I can look for while setting up the 
valgrind tests? Is there a possibility I am linking with incorrect 
systems libraries?

Thomas Anders wrote:
> Mike Schmidt wrote:
>   
>> I have net-snmp 5.4 running on
>>
>> - RH8 and CentOS 4.4 systems (compiled with no options to configure)
>> - Solaris 10. (compiled without embedded-perl because of perl issues)
>>
>> I also have some copies of 5.1.2 (the official CentOS version) installed
>> as binary from the CentOS distribution.
>>
>> In all of these installations, both snmpd and snmptrapd suck up memory
>> until the system runs out of swap space and dies.
>>     
>
> We'd need more information to be able to help:
>
> 1) Run snmpd and snmptrapd under valgrind (or the like) and tell us the results
>
> 2) For snmpd, what objects are you querying and how often? For snmptrapd, what
> notifications does it get and how often? Is this all over UDP/IPv4 transport? Is
> there anything special about these systems (e.g. transient interfaces like ppp)?
>
>
> +Thomas
>
>

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