Re: Net-SNMP crash when AgentX SubAgent times out

Hi David,

yes there are a few patches that fixes this issue, I suggest the you use
the latest code from [email protected]:net-snmp/net-snmp.git

Regards
Anders Wallin


On Wed, Nov 27, 2019 at 10:17 PM David Moriconi (dmoricon) via
Net-snmp-coders <[email protected]> wrote:

> Hi,
>
> I am using Net-SNMP version 5.8 on CentOS 6.8 as a master agent with an
> AgentX SubAgent.
>
>
>
> When my AgentX SubAgent takes too much time to respond and times out, the
> Net-SNMP daemon crashes. I have searched for this issue and found
> https://github.com/net-snmp/net-snmp/commit/793d596838ff7cb48a73b675d62897c56c9e62df
> but this seems to be already included in version 5.8.
>
>
>
> Is this a known issue? Is it already patched? If so, where can I find the
> patch?
>
>
>
> Here is the crash dump that I have in my log when this happens:
>
> Unknown operation 6 in agentx_got_response
>
> *** glibc detected *** /usr/local/netsnmp/netsnmp_base/sbin/snmpd:
> malloc(): smallbin double linked list corrupted: 0x00005603745c4110 ***
>
> ======= Backtrace: =========
>
> /lib64/libc.so.6(+0x3a24675e5e)[0x7fc9d5d72e5e]
>
> /lib64/libc.so.6(+0x3a2467a528)[0x7fc9d5d77528]
>
> /lib64/libc.so.6(__libc_malloc+0x5c)[0x7fc9d5d77b1c]
>
> /lib64/libc.so.6(vasprintf+0x140)[0x7fc9d5d6c340]
>
> /usr/local/netsnmp/5.8/lib/libnetsnmp.so.35(snmp_vlog+0x42)[0x7fc9d709ea9c]
>
> /usr/local/netsnmp/5.8/lib/libnetsnmp.so.35(snmp_log+0xb9)[0x7fc9d709ebb3]
>
>
> /usr/local/netsnmp/5.8/lib/libnetsnmpagent.so.35(agentx_got_response+0x669)[0x7fc9d78e2586]
>
> /usr/local/netsnmp/5.8/lib/libnetsnmp.so.35(+0x5778c)[0x7fc9d707c78c]
>
>
> /usr/local/netsnmp/5.8/lib/libnetsnmp.so.35(snmp_sess_timeout+0x2a5)[0x7fc9d707ca54]
>
>
> /usr/local/netsnmp/5.8/lib/libnetsnmp.so.35(snmp_timeout+0x33)[0x7fc9d707c0f0]
>
> /usr/local/netsnmp/netsnmp_base/sbin/snmpd(+0x5081)[0x5603723c3081]
>
> /usr/local/netsnmp/netsnmp_base/sbin/snmpd(main+0x19b8)[0x5603723c28ac]
>
> /lib64/libc.so.6(__libc_start_main+0x100)[0x7fc9d5d1bd20]
>
> /usr/local/netsnmp/netsnmp_base/sbin/snmpd(+0x2b79)[0x5603723c0b79]
>
> ======= Memory map: ========
>
> 5603723be000-5603723c5000 r-xp 00000000 fc:05 405833
>                     /usr/local/netsnmp/5.8/sbin/snmpd
>
> 5603725c4000-5603725c5000 r--p 00006000 fc:05 405833
> /usr/local/netsnmp/5.8/sbin/snmpd
>
> 5603725c5000-5603725c6000 rw-p 00007000 fc:05 405833
> /usr/local/netsnmp/5.8/sbin/snmpd
>
> 56037444d000-5603745ee000 rw-p 00000000 00:00 0
> [heap]
>
> 7fc9c8000000-7fc9c8021000 rw-p 00000000 00:00 0
>
> 7fc9c8021000-7fc9cc000000 ---p 00000000 00:00 0
>
> 7fc9ceeaa000-7fc9ceec0000 r-xp 00000000 fc:05 1315920
>      /lib64/libgcc_s-4.4.7-20120601.so.1
>
> 7fc9ceec0000-7fc9cf0bf000 ---p 00016000 fc:05 1315920
> /lib64/libgcc_s-4.4.7-20120601.so.1
>
> 7fc9cf0bf000-7fc9cf0c0000 rw-p 00015000 fc:05 1315920
> /lib64/libgcc_s-4.4.7-20120601.so.1
>
> 7fc9cf0c0000-7fc9cf0cd000 r-xp 00000000 fc:05 1310749
> /lib64/libnss_files-2.12.so
>
> 7fc9cf0cd000-7fc9cf2cc000 ---p 0000d000 fc:05 1310749
> /lib64/libnss_files-2.12.so
>
> 7fc9cf2cc000-7fc9cf2cd000 r--p 0000c000 fc:05 1310749
> /lib64/libnss_files-2.12.so
>
> 7fc9cf2cd000-7fc9cf2ce000 rw-p 0000d000 fc:05 1310749
> /lib64/libnss_files-2.12.so
>
> 7fc9cf2ce000-7fc9d5163000 r--p 00000000 fc:05 402284
>                    /usr/lib/locale/locale-archive
>
> 7fc9d5163000-7fc9d5165000 r-xp 00000000 fc:05 1315924
> /lib64/libfreebl3.so
>
> 7fc9d5165000-7fc9d5364000 ---p 00002000 fc:05 1315924
> /lib64/libfreebl3.so
>
> 7fc9d5364000-7fc9d5365000 r--p 00001000 fc:05 1315924
> /lib64/libfreebl3.so
>
> 7fc9d5365000-7fc9d5366000 rw-p 00002000 fc:05 1315924
> /lib64/libfreebl3.so
>
> 7fc9d5366000-7fc9d53e9000 r-xp 00000000 fc:05 1315917
> /lib64/libm-2.12.so
>
> 7fc9d53e9000-7fc9d55e8000 ---p 00083000 fc:05 1315917
> /lib64/libm-2.12.so
>
> 7fc9d55e8000-7fc9d55e9000 r--p 00082000 fc:05 1315917
> /lib64/libm-2.12.so
>
> 7fc9d55e9000-7fc9d55ea000 rw-p 00083000 fc:05 1315917
>           /lib64/libm-2.12.so
>
> 7fc9d55ea000-7fc9d58c5000 r-xp 00000000 fc:05 403870
> /usr/local/ssl/1.0.2s/lib/libcrypto.so.1.0.0
>
> 7fc9d58c5000-7fc9d5ac4000 ---p 002db000 fc:05 403870
> /usr/local/ssl/1.0.2s/lib/libcrypto.so.1.0.0
>
> 7fc9d5ac4000-7fc9d5ae3000 r--p 002da000 fc:05 403870
> /usr/local/ssl/1.0.2s/lib/libcrypto.so.1.0.0
>
>
>
>
>
> Thank you,
>
>
>
>
>
> [image:
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>
> *David Moriconi*
>
> Software Engineer
>
> [email protected]
>
> Tel: *5143333808*
>
> Cisco Systems Canada Co. / Les Systemes Cisco Canada CIE
>
> Cisco.com <http://www.cisco.com/web/CA/>
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