[ECOS] Re: SNMP lockup

Sergei Gavrikov sergei.gavrikov@gmail.com
Fri May 8 23:10:00 GMT 2009


On Fri, May 08, 2009 at 10:38:24PM +0000, Grant Edwards wrote:
> On 2009-05-08, Sergei Gavrikov <sergei.gavrikov@gmail.com> wrote:
> 
> > If your guess is right...
> 
> It's not a guess.
> 
> The problem occurs when cyg_snmp_get_if() is called with if_num <= 0.
> 
> The loop takes 1-2 minutes to loop from -1, -2, back to 0,
> causing the SNMP management thread to lock out all lower
> priority threads while it's doing so.

Then fix it.

> 
> > Can you walk here with/without tweaks when if_num=0
> >
> > repo/devo/ecos/packages/net/snmp/agent/current/src/mibgroup/mibII/interfaces.c:398
 
[snip]

> I'm surprised nobody else has run into this.  I'm told all our
> customers who have HP or Cisco SNMP managers have had to
> disable SNMP support in our products to keep them from locking
> up every few minutes.

I was just googling +'ifPhysAddress.0'

It seems you are not alone :-)

http://mtsc.moxa.com:8888/Software/DN/NPort/Firmware/NPort%205000/NPort%205600/ver3.2/VERSION.TXT

<quote>
ver3.1 (2006/05/16)

3. Fixed the problem that querying NPort by SNMP Software would cause NPort stop replying ethernet packet

   while querying "GET iso.3.6.1.2.1.2.2.1.6.0", which is resolved as

   "GET iso.org.dod.internet.mgmt.mib-2.interface.ifTable.ifEntry.ifPhysAddress.0".
</quote>


UCD-SNMP had a lot of holes. eCos UCD-SNMP implementation has even more
holes :-(


Good luck!

Sergei

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