Big memory leak in 5.3.1 when traps are sent

Hi All,

When I tried to run an application Cacti to collect network info , such as the memory and cpu usages by the application, I found there is a memory leak in net-snmp. The Cacti is running on a Windows box, which connects to a Linux box running net-snmp 5.3.1. The following is the debug info using Valgrind:

==2214== ERROR SUMMARY: 744 errors from 16 contexts (suppressed: 0 from 0)
==2214== malloc/free: in use at exit: 502,770 bytes in 12,618 blocks.
==2214== malloc/free: 20,963 allocs, 8,345 frees, 29,211,624 bytes allocated.
==2214== For counts of detected errors, rerun with: -v
==2214== searching for pointers to 12,618 not-freed blocks.
==2214== checked 990,336 bytes.
==2214==
==2214==
==2214== 24 bytes in 1 blocks are definitely lost in loss record 29 of 94
==2214==    at 0x402CB70: calloc (in /opt/2/lib/valgrind/ppc32-linux/vgpreload_m
emcheck.so)
==2214==    by 0x4239878: netsnmp_container_get_binary_array (in /lib/libnetsnmp
.so.10.0.1)
==2214==    by 0x4238D98: netsnmp_container_find (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x40D82F8: _snmpNotifyFilterTable_initialize_interface (in /lib/l
ibnetsnmpmibs.so.10.0.1)
==2214==    by 0x40B0F9C: initialize_table_snmpNotifyFilterTable (in /lib/libnet
snmpmibs.so.10.0.1)
==2214==    by 0x40B10A0: init_snmpNotifyFilterTable (in /lib/libnetsnmpmibs.so.
10.0.1)
==2214==    by 0x40F58F4: init_mib_modules (in /lib/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x100041DC: (within /sbin/snmpd)
==2214==    by 0x44F3CB8: __uClibc_main (in /lib/libuClibc-0.9.29.so)
==2214==
==2214==
==2214== 40 bytes in 10 blocks are definitely lost in loss record 37 of 94
==2214==    at 0x402DBC0: malloc (in /opt/2/lib/valgrind/ppc32-linux/vgpreload_m
emcheck.so)
==2214==    by 0x419A20C: register_agentx_list (in /lib/libnetsnmpagent.so.10.0.
1)
==2214==    by 0x419AB24: handle_master_agentx_packet (in /lib/libnetsnmpagent.s
o.10.0.1)
==2214==    by 0x420C148: (within /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x420D4FC: _sess_read (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x420D800: snmp_sess_read (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x420D86C: snmp_read (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x10004BE8: (within /sbin/snmpd)
==2214==    by 0x44F3CB8: __uClibc_main (in /lib/libuClibc-0.9.29.so)
==2214==
==2214==
==2214== 12,996 (168 direct, 12,828 indirect) bytes in 7 blocks are definitely l
ost in loss record 80 of 94
==2214==    at 0x402CB70: calloc (in /opt/2/lib/valgrind/ppc32-linux/vgpreload_m
emcheck.so)
==2214==    by 0x41CC188: netsnmp_create_table_data_row (in /lib/libnetsnmphelpe
rs.so.10)
==2214==    by 0x408B384: log_notification (in /lib/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x4088AF0: send_notifications (in /lib/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x4225814: snmp_call_callbacks (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x4183754: netsnmp_send_traps (in /lib/libnetsnmpagent.so.10.0.1)
==2214==    by 0x4183794: send_enterprise_trap_vars (in /lib/libnetsnmpagent.so.
10.0.1)
==2214==    by 0x41837F4: send_trap_vars (in /lib/libnetsnmpagent.so.10.0.1)
==2214==    by 0x4199DD4: agentx_notify (in /lib/libnetsnmpagent.so.10.0.1)
==2214==    by 0x419ABA4: handle_master_agentx_packet (in /lib/libnetsnmpagent.s
o.10.0.1)
==2214==    by 0x420C148: (within /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x420D4FC: _sess_read (in /lib/libnetsnmp.so.10.0.1)
==2214==
==2214==
==2214== 172 bytes in 1 blocks are definitely lost in loss record 81 of 94
==2214==    at 0x402CB70: calloc (in /opt/2/lib/valgrind/ppc32-linux/vgpreload_m
emcheck.so)
==2214==    by 0x40E46DC: netsnmp_access_systemstats_entry_update_stats (in /lib
/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x40E49D0: netsnmp_access_systemstats_entry_update (in /lib/libne
tsnmpmibs.so.10.0.1)
==2214==    by 0x40CC934: (within /lib/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x423960C: (within /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x40CC5F8: ipSystemStatsTable_container_load (in /lib/libnetsnmpm
ibs.so.10.0.1)
==2214==    by 0x40CB564: (within /lib/libnetsnmpmibs.so.10.0.1)
==2214==    by 0x41C0F78: (within /lib/libnetsnmphelpers.so.10)
==2214==    by 0x42276D8: run_alarms (in /lib/libnetsnmp.so.10.0.1)
==2214==    by 0x10004CD0: (within /sbin/snmpd)
==2214==    by 0x44F3CB8: __uClibc_main (in /lib/libuClibc-0.9.29.so)

==2217== 4,171,676 (54,144 direct, 4,117,532 indirect) bytes in 2,256 blocks are definitely lost in loss record 92 of 96
==2217==    at 0x402CB70: calloc (in /opt/2/lib/valgrind/ppc32-linux/vgpreload_m
emcheck.so)
==2217==    by 0x41CC188: netsnmp_create_table_data_row (in /lib/libnetsnmphelpe
rs.so.10)
==2217==    by 0x408B384: log_notification (in /lib/libnetsnmpmibs.so.10.0.1)
==2217==    by 0x4088AF0: send_notifications (in /lib/libnetsnmpmibs.so.10.0.1)
==2217==    by 0x4225814: snmp_call_callbacks (in /lib/libnetsnmp.so.10.0.1)
==2217==    by 0x4183754: netsnmp_send_traps (in /lib/libnetsnmpagent.so.10.0.1)
==2217==    by 0x4183794: send_enterprise_trap_vars (in /lib/libnetsnmpagent.so.
10.0.1)
==2217==    by 0x41837F4: send_trap_vars (in /lib/libnetsnmpagent.so.10.0.1)
==2217==    by 0x4199DD4: agentx_notify (in /lib/libnetsnmpagent.so.10.0.1)
==2217==    by 0x419ABA4: handle_master_agentx_packet (in /lib/libnetsnmpagent.s
o.10.0.1)
==2217==    by 0x420C148: (within /lib/libnetsnmp.so.10.0.1)
==2217==    by 0x420D4FC: _sess_read (in /lib/libnetsnmp.so.10.0.1)

By looking at the function that causes the most of memory leak, it looks like when the function netsnmp_create_table_data_row() calloc memories, it fails to deallocate when a trap is sent out but for some reason, the trap packet failed to reach the host.

Is this memory leak a known issue? Has it been fixed in the latest release?

Cheers, Henry

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