Memory leak in UDP input plugin

[ghost]

From time to time, I get the following report from Valgrind:

==26923== 10 bytes in 2 blocks are definitely lost in loss record 12 of 153
==26923==    at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==26923==    by 0x69E04B0: input_init (udp_input.c:159)
==26923==    by 0x408F14: config_add_input (configurator.c:355)
==26923==    by 0x409F4A: config_process_new_startup (configurator.c:681)
==26923==    by 0x40A2A7: config_reconf (configurator.c:1133)
==26923==    by 0x406EDF: main (ipfixcol.c:340)

There's no clear way to reproduce this issue (it just happens from time to time), although I cannot pinpoint the source of the problem, yet. What I can say though is that the issue is not solved by checking whether the variables in udp_input.c:181,183,185,187 are already set before (over)writing the pointer.

[thorgrin]

I do not see how the leak is possible at the moment. The only case when this leak occurs is when I'm terminating the collector with second signal - in case it won't die the first time. Can you provide more information about when this happens?

[ghost]

Same for me. I spent quite some time trying to debug this problem, but without any luck so far. I'm certainly not running terminating the collector with a second signal. Some observations:

• I see the issue roughly 90% of all times that I run the collector. What I do is the following:
  • Start IPFIXcol with Valgrind
  • Send some data to IPFIXcol using tcpreplay
  • Send SIGTERM to IPFIXcol (once), as soon as data replay has finished
• There is no leak if there is no input data.
• The issue seems to be independent from a specific trace.
• I'm using a UDP input plugin config that looks as follows:

<collectingProcess>
    <name>UDP collector</name>
    <udpCollector>
        <name>Listening port 3055</name>
        <localPort>3055</localPort>
        <templateLifeTime>1800</templateLifeTime>
        <optionsTemplateLifeTime>1800</optionsTemplateLifeTime>
        <!--## Local address to listen on. If empty, bind to all interfaces -->
        <localIPAddress></localIPAddress>
    </udpCollector>
    <exportingProcess>Integrated export</exportingProcess>
    <statisticsFile>ipfixcol_stat.log</statisticsFile>
</collectingProcess>

• While debugging, I was triggered by the following comment in configurator.c:

/* Input is pointer to configurator structure, don't free it */
// free(plugin->input);

By the way, as a precaution, I added some extra checks to udp_input.c as part of #72.

[thorgrin]

I've tried with ipfix storage plugin and data is send by ipfixsend tool. There are no leaks at all. Maybe the valgrind does not handle dynamically loading plugins correctly?

[ghost]

Just checking: which version of Valgrind are you using? I'm using valgrind-3.10.0.SVN.

[thorgrin]

I'm using valgrind-3.8.1 which comes with OpenSuse 12.3. Can you try the same test on other versions?

[ghost]

Since valgrind-3.8.1 is rather old, I tested it again on Valgrind's latest-and-greatest release, valgrind-3.10.1.SVN, and the leak is still reported.

[thorgrin]

I've just tested it with valgrind-3.11.0.SVN and still I'm not able to reproduce the issue. I'm gonna close it until we can reproduce it more reliably.