Description of problem: If you have disabled ipv6 on RHEL 5 x86_64 via the modprobe.conf, running snmpwalk -v2c -c community 127.0.0.1 will spike a single CPU. Version-Release number of selected component (if applicable): This is applicable to every release of net-snmp since 5.1 ISOs were released. The lastest version I have tried is is in the RHEL 5.2 Beta channel. net-snmp-5.3.1-2 How reproducible: Always Steps to Reproduce: 1. Run RHEL 5.1 or newer x86_64 2. Disable IPv6 via the modprobe.conf 3. reboot 4. service snmpd start 5. snmpwalk -v2c -c community 127.0.0.1 6. Look at top output, watch a CPU sit at 100% Actual results: I have included attachments for the commands. Expected results: Not having 100% spike while snmpd is running. Additional info: It appears to be happening on at least these MIBS .1.3.6.1.2.1.4.34 .1.3.6.1.2.1.4.35 I have included the following: snmpd.conf snmpwalk_output_normal strace_snmpwalk var_log_messages_snip output_from_top I also tried to rebuild the SRPM disabling Ipv6, but the build fails. I am not sure if that is considered a bug though. It appears that this bug isn't new. Google told me it's been happing in Centos 4, and 5 also. Here's a link with some information from the CentOS crew. http://bugs.centos.org/view.php?id=1350
Created attachment 303824 [details] This is a slightly sanitized version of our snmpd.conf
Created attachment 303825 [details] The output of snmpwalk (not straced anything)
Created attachment 303826 [details] The output from top showing a cpu is 100% used
Created attachment 303827 [details] strace running with snmpwalk
Created attachment 303828 [details] And a bit of /var/log/messages
I see the same bug. Additionally, snmpd must be restarted after a snmpwalk of the server to get snmpget's or walks working again. Some people have reported this is a xen kernel issue, but this happens for us on non-xen kernels.
It should be already fixed in RHEL 5.2. It has nothing to do with xen and it happens only with RHEL 5.1 (I've added a buggy patch there). *** This bug has been marked as a duplicate of 431977 ***
This is not fixed in the currently released net-snmp inthe RHEL 5.2 beta channel. I have the latest net-snmp installed that is available in RHN. net-snmp-5.3.1-22 If there is a fix, could you direct me to the link? The other bug says proposed for RHEL 5.3. I would like a fix before 2009.
it was fixed after beta, in net-snmp-5.3.1-23 to be precise. And the bug has been evaluated as important enough to fix it in 5.2. You can find test build at http://people.redhat.com/jsafrane/bugs/444236/
Thank you very much for a prompt response. Everything working just fine.