Hi!
I'm using SNMP4J for monitoring around 200 devices. It has been running stably
for months. Now I found a problem in the latest releases: When my process runs
for a couple of hours (sometimes days), after some time SNMP4J returns nothing
but timeouts. My program initially uses Snmp.send() and TableUtils (I think,
this doesn't matter). After the problem shows up once, all my program
effectively does is querying the SysObjectIds (because this already results in
timeouts):
org.snmp4j.Snmp.send(get(SnmpV2Mib.sysObjectID), target)
Some of the targets are community targets, some are user targets, but I get
timeouts for all devices. I repeated testing with only community targets
resulting in the same behavior. I tracked down the problem to release 2.5.7.
The previous version 2.5.6 works without problems, all releases starting with
2.5.7 show the problem. I also analyzed the SNMP packages using tcpdump. The
devices send their answers quickly, the packets don't look any special. It
seems that SNMP4J doesn't receive, recognize or process the UDP packets.
Can you reproduce the problem? Does anyone see problems in source code changes
from 2.5.6 to 2.5.7?
Best regards
Steffen Brüntjen
Here are some stacktraces at the time the problem exists:
"DefaultUDPTransportMapping_0.0.0.0/162" #72 daemon prio=5 os_prio=0
tid=0x00007fa0ac00a000 nid=0x4433 runnable [0x00007fa08b4f3000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainDatagramSocketImpl.receive0(Native Method)
- locked <0x0000000089977c28> (a java.net.PlainDatagramSocketImpl)
at
java.net.AbstractPlainDatagramSocketImpl.receive(AbstractPlainDatagramSocketImpl.java:143)
- locked <0x0000000089977c28> (a java.net.PlainDatagramSocketImpl)
at java.net.DatagramSocket.receive(DatagramSocket.java:812)
- locked <0x0000000089b2b3a8> (a java.net.DatagramPacket)
- locked <0x0000000089977c78> (a java.net.DatagramSocket)
at
org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(DefaultUdpTransportMapping.java:397)
at java.lang.Thread.run(Thread.java:745)
"DefaultUDPTransportMapping_0.0.0.0/0" #33 daemon prio=5 os_prio=0
tid=0x00007fa126c9d800 nid=0x440c in Object.wait() [0x00007fa0b60f1000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool.execute(ThreadPool.java:103)
- locked <0x00000000883cde50> (a org.snmp4j.util.ThreadPool)
at
org.snmp4j.util.MultiThreadedMessageDispatcher.processMessage(MultiThreadedMessageDispatcher.java:162)
at
org.snmp4j.transport.AbstractTransportMapping.fireProcessMessage(AbstractTransportMapping.java:76)
at
org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(DefaultUdpTransportMapping.java:430)
at java.lang.Thread.run(Thread.java:745)
"snmp.3" #37 prio=5 os_prio=0 tid=0x00007fa125a38000 nid=0x4410 in
Object.wait() [0x00007fa0b5ced000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:275)
- locked <0x00000000883ddeb8> (a org.snmp4j.util.ThreadPool$TaskManager)
"snmp.2" #36 prio=5 os_prio=0 tid=0x00007fa126ca1800 nid=0x440f in
Object.wait() [0x00007fa0b5dee000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:275)
- locked <0x00000000883de0c8> (a org.snmp4j.util.ThreadPool$TaskManager)
"snmp.1" #35 prio=5 os_prio=0 tid=0x00007fa126ca0800 nid=0x440e in
Object.wait() [0x00007fa0b5eef000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:275)
- locked <0x00000000883de2d8> (a org.snmp4j.util.ThreadPool$TaskManager)
"snmp.0" #34 prio=5 os_prio=0 tid=0x00007fa126ca0000 nid=0x440d in
Object.wait() [0x00007fa0b5ff0000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:275)
- locked <0x00000000883de4e8> (a org.snmp4j.util.ThreadPool$TaskManager)
"trap.0" #71 prio=5 os_prio=0 tid=0x00007fa0ac004000 nid=0x4432 in
Object.wait() [0x00007fa08b5f4000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.snmp4j.util.ThreadPool$TaskManager.run(ThreadPool.java:275)
- locked <0x0000000089979080> (a org.snmp4j.util.ThreadPool$TaskManager)
And then there are some monitoring threads that send SNMP queries:
"mon-001" #43 prio=5 os_prio=0 tid=0x00007fa0c000c000 nid=0x4416 in
Object.wait() [0x00007fa0b52e7000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at org.snmp4j.Snmp.send(Snmp.java:991)
- locked <0x00000000fdc0c6e0> (a org.snmp4j.Snmp$SyncResponseListener)
at org.snmp4j.Snmp.send(Snmp.java:963)
at org.snmp4j.Snmp.send(Snmp.java:928)
at [...]
And here's some non-binary tcpdump output:
12:05:49.820810 IP 192.168.101.211.57522 > 10.100.7.204.snmp: GetRequest(28)
system.sysObjectID.0
E..G..@.@[email protected].
d.......38.0).....public..../.........0.0...+.........
12:05:49.821321 IP 10.100.7.204.snmp > 192.168.101.211.57522: GetResponse(37)
system.sysObjectID.0=E:cisco.1.614
E..P..@[email protected]
d....e......<..02.....public.%../.........0.0...+........ +.... ..f
^C
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