<div dir="ltr">Björn-Egil,<br><br>I reported this bug for R12B-2, and only just got back to working with SNMP. I see that this bug is still present in R12B-3. I'm not surprised, seeing that R12B-3 was released on June 11 and I only reported the issue on May 28. That's not nearly enough time to fix and test it.<br>
<br>Will it be fixed for the next release?<br><br>Regards,<br>Edwin Fine<br><br><div class="gmail_quote">On Mon, Jun 2, 2008 at 5:39 AM, Björn-Egil Dahlberg <span dir="ltr"><<a href="mailto:egil@erix.ericsson.se">egil@erix.ericsson.se</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Thank you for pointing out this problem.<br>
<br>
I will look into it.<br>
<br>
Regards,<br>
Björn-Egil<br>
Erlang/OTP<br>
<br>
Edwin Fine wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d">
I need to thank Martin Bjorkland for helping me recognize this bug.<br>
<br>
I believe that the file OTP-OS-MON-MIB.mib has two sets of bugs, one more serious than the other. Fixing the first bug also showed up a potential third bug (see later).<br>
<br>
*The More Serious One*<br>
<br>
The following objects in OTP-OS-MON-MIB.mib are defined as type Gauge32, and cause problems when the values returned are actually greater than a 32-bit value can represent:<br>
<br>
loadSystemTotalMemory Gauge32,<br>
loadSystemUsedMemory Gauge32,<br>
loadLargestErlProcessUsedMemory Gauge32,<br>
<br>
To reproduce this problem, simply do an snmpwalk on a 64-bit system that has more than 4 GB of memory (mine is Ubuntu 7.10 x86_64 with 8 GB) and try to get the loadSystemTotalMemory.0 object.<br>
<br>
*Example of error:*<br>
<br></div>
$ snmpwalk -m ALL -u initial <a href="http://127.0.0.1:4000" target="_blank">127.0.0.1:4000</a> <<a href="http://127.0.0.1:4000" target="_blank">http://127.0.0.1:4000</a>> loadSystemTotalMemory.0<div class="Ih2E3d">
<br>
Error in packet.<br>
Reason: (genError) A general failure occured<br>
Failed object: OTP-OS-MON-MIB::loadSystemTotalMemory.""<br>
<br>
OTP-OS-MON-MIB::loadSystemTotalMemory."" = No Such Instance currently exists at this OID<br>
<br>
-------------<br>
*Agent error message*<br>
<br>
I believe the agent error message below shows that the value of 8386678784 (not coincidentally, about 8 GB) is out of range.<br>
<br>
=ERROR REPORT==== 28-May-2008::00:26:03 ===<br>
** User error: Got 8386678784 from {os_mon_mib,load_table,[]}. Using wrongValue<br>
<br>
--------------<br>
*Proposed Solution*<br>
<br>
The solution according to Martin is to change the Gauge32 types to be CounterBasedGauge64, from HCNUM-TC.<br>
<br>
I tried this in OTP-OS-MON-MIB as follows:<br>
<br></div>
1. cd /usr/local/lib/erlang/lib/os_mon-2.1.5/mibs<br>
2. cp OTP-OS-MON-MIB.mib OTP-OS-MON-MIB.mib.buggy<br>
3. (Modified OTP-OS-MON-MIB.mib as shown in the diff output at the<br>
end of this email.)<br>
4. cp /usr/share/snmp/mibs/HCNUM-TC.txt ./HCNUM-TC.mib<br>
5. erlc -o ../priv/mibs/ -I ../priv/mibs -I<div class="Ih2E3d"><br>
../../otp_mibs-1.0.4.1/priv/mibs HCNUM-TC.mib OTP-OS-MON-MIB.mib<br></div>
6. Reloaded the agent<div><div></div><div class="Wj3C7c"><br>
<br>
This fixed the error, but exposed another possible bug. If otp-mib is not loaded into the agent, then the snmpwalk causes this error below. This is reproducible. I would think that if otp-mib was absent, the agent would at least show that a required dependency was not loaded and not crash.<br>
<br>
*** [2008:05:28 22:07:30 4113] SNMP MASTER-AGENT LOG ***<br>
apply: os_mon_mib,disk_table,[get_next,[],[0]]<br>
<br>
*** [2008:05:28 22:07:30 4113] SNMP MASTER-AGENT INFO ***<br>
Call to:<br>
Module: os_mon_mib<br>
Function: disk_table<br>
Args: [get_next,[],[0]]<br>
<br>
resulted in an exit<br>
<br>
{{badmatch,false},<br>
[{snmp_generic,table_info,1},<br>
{snmp_generic_mnesia,table_func,4},<br>
{os_mon_mib,update_disk_table,0},<br>
{snmp_shadow_table,update,3},<br>
{snmp_shadow_table,table_func,4},<br>
{snmpa_agent,dbg_apply,3},<br>
{snmpa_agent,get_next_values_all_rows,6},<br>
{snmpa_agent,get_next_table,4}]}<br>
<br>
=ERROR REPORT==== 28-May-2008::18:07:30 ===<br>
** User error: Invalid return value {'EXIT',{{badmatch,false},[{snmp_generic,table_info,1},{snmp_generic_mnesia,table_func,4},{os_mon_mib,update_disk_table,0},{snmp_shadow_table,update,3},{snmp_shadow_table,table_func,4},{snmpa_agent,dbg_apply,3},{snmpa_agent,get_next_values_all_rows,6},{snmpa_agent,get_next_table,4}]}} from {os_mon_mib,disk_table,[]} (get_next)<br>
--------------------------------------<br>
----------------------<br>
$ diff -U 0 OTP-OS-MON-MIB.mib.buggy OTP-OS-MON-MIB.mib<br>
--- OTP-OS-MON-MIB.mib.buggy 2008-05-06 10:02:27.000000000 -0400<br>
+++ OTP-OS-MON-MIB.mib 2008-05-28 17:28:42.000000000 -0400<br>
@@ -14,0 +15,2 @@<br>
+ CounterBasedGauge64<br>
+ FROM HCNUM-TC<br>
@@ -111,2 +113,2 @@<br>
- loadSystemTotalMemory Gauge32,<br>
- loadSystemUsedMemory Gauge32,<br>
+ loadSystemTotalMemory CounterBasedGauge64,<br>
+ loadSystemUsedMemory CounterBasedGauge64,<br>
@@ -114 +116 @@<br>
- loadLargestErlProcessUsedMemory Gauge32,<br>
+ loadLargestErlProcessUsedMemory CounterBasedGauge64,<br>
@@ -129 +131 @@<br>
- SYNTAX Gauge32<br>
+ SYNTAX CounterBasedGauge64<br>
@@ -138 +140 @@<br>
- SYNTAX Gauge32<br>
+ SYNTAX CounterBasedGauge64<br>
@@ -156 +158 @@<br>
- SYNTAX Gauge32<br>
+ SYNTAX CounterBasedGauge64<br>
@@ -283,4 +285,4 @@<br>
- GROUP loadAlarmsGroup<br>
- DESCRIPTION<br>
- "This group is optional for systems implementing the<br>
- load supervison functionality."<br>
+ --GROUP loadAlarmsGroup<br>
+ --DESCRIPTION<br>
+ -- "This group is optional for systems implementing the<br>
+ -- load supervison functionality."<br>
@@ -291,4 +293,4 @@<br>
- GROUP diskAlarmsGroup<br>
- DESCRIPTION<br>
- "This group is optional for systems implementing the<br>
- disk supervison functionality."<br>
+ --GROUP diskAlarmsGroup<br>
+ --DESCRIPTION<br>
+ -- "This group is optional for systems implementing the<br>
+ -- disk supervison functionality."<br>
<br>
--------------------------------------------<br>
*The less serious bug<br>
<br>
*Maybe this is not a bug, but two groups are referenced that do not exist in OTP-OS-MON-MIB.mib:<br>
<br>
GROUP loadAlarmsGroup<br>
GROUP diskAlarmsGroup<br>
<br>
This causes snmpwalk to emit error messages. Commenting out the above lines seemed to have no effect other than stopping the snmpwalk error messages.<br>
<br>
Regards,<br>
Edwin Fine<br>
<br>
<br></div></div>
------------------------------------------------------------------------<br>
<br>
_______________________________________________<br>
erlang-bugs mailing list<br>
<a href="mailto:erlang-bugs@erlang.org" target="_blank">erlang-bugs@erlang.org</a><br>
<a href="http://www.erlang.org/mailman/listinfo/erlang-bugs" target="_blank">http://www.erlang.org/mailman/listinfo/erlang-bugs</a><br>
</blockquote>
<br>
<br>
</blockquote></div><br><br clear="all"><br>-- <br>For every expert there is an equal and opposite expert - Arthur C. Clarke<br>
</div>