Hi Josef, I can reproduce the issue using the master branch, I will take a look at it later tonight or tomorrow
Regards Anders Wallin On Tue, Apr 2, 2019 at 3:42 PM Josef Ridky <jri...@redhat.com> wrote: > Hi, > > thanks for your patch. Unfortunately, even when I have applied it, it > still ends with core dump due of 'double free or corruption (fasttop)' > > When I run snmpd with -Dsnmp_agent,agentx/master it ends with: > > agentx/master: sending pdu (req=0x1d4,trans=0x1d3,sess=0x5) > snmp_agent: delegate session == 0x56207e165240 > snmp_agent: end of handle_snmp_packet, asp = 0x56207e165240 > agentx/master: callback resend > agentx/master: callback resend > agentx/master: timeout on session 0x56207dfd5400 req=0x1c9 > agentx/master: close 0x56207dfd5400, -1 > snmp_agent: removed 40 delegated request(s) for session 0x56207dfce490 > snmp_agent: processing delegated request, asp = 0x56207e165240 > snmp_agent: canceling next walk for asp 0x56207e165240 > snmp_agent: REMOVE session == 0x56207e165240 > snmp_agent: agent_session 0x56207e165240 released > snmp_agent: processing delegated request, asp = 0x56207e1041a0 > snmp_agent: canceling next walk for asp 0x56207e1041a0 > snmp_agent: REMOVE session == 0x56207e1041a0 > snmp_agent: agent_session 0x56207e1041a0 released > snmp_agent: processing delegated request, asp = 0x56207e1656c0 > snmp_agent: canceling next walk for asp 0x56207e1656c0 > snmp_agent: REMOVE session == 0x56207e1656c0 > snmp_agent: agent_session 0x56207e1656c0 released > snmp_agent: processing delegated request, asp = 0x56207e11af40 > snmp_agent: canceling next walk for asp 0x56207e11af40 > snmp_agent: REMOVE session == 0x56207e11af40 > snmp_agent: agent_session 0x56207e11af40 released > snmp_agent: processing delegated request, asp = 0x56207e118f00 > snmp_agent: canceling next walk for asp 0x56207e118f00 > snmp_agent: REMOVE session == 0x56207e118f00 > snmp_agent: agent_session 0x56207e118f00 released > snmp_agent: processing delegated request, asp = 0x56207e11b540 > snmp_agent: canceling next walk for asp 0x56207e11b540 > snmp_agent: REMOVE session == 0x56207e11b540 > snmp_agent: agent_session 0x56207e11b540 released > snmp_agent: processing delegated request, asp = 0x56207e11bd00 > snmp_agent: canceling next walk for asp 0x56207e11bd00 > snmp_agent: REMOVE session == 0x56207e11bd00 > snmp_agent: agent_session 0x56207e11bd00 released > agentx/master: Continue removing delegated subsession reqests > agentx/master: close transport > snmp_agent: REMOVE session == 0x56207dfd5400 > agentx/master: response too late on session 0x56207dfd5400 > agentx/master: response too late on session 0x56207dfd5400 > double free or corruption (fasttop) > Aborted (core dumped) > > > What's interesting, when I run it with -DALL it pass (at least for several > rounds). > It looks like some strange race condition. > > Regards > > Josef Ridky > Software Engineer > Core Services Team > Red Hat Czech, s.r.o. > > ----- Original Message ----- > | From: "Anders Wallin" <walli...@gmail.com> > | To: "Josef Ridky" <jri...@redhat.com> > | Cc: "net-snmp-coders" <net-snmp-coders@lists.sourceforge.net> > | Sent: Tuesday, April 2, 2019 1:46:40 PM > | Subject: Re: Core dump with net-snmp-5.8 > | > | Hi Josef, > | > | I think it's the same issue as > https://sourceforge.net/p/net-snmp/bugs/2914/ > | (where I also posted the solution) > | Regards > | Anders Wallin > | > | > | On Tue, Apr 2, 2019 at 12:43 PM Josef Ridky <jri...@redhat.com> wrote: > | > | > Hi, > | > > | > recently, I have hit to an issue in net-snmp-5.8, that is connected to > the > | > bug report [1]. > | > > | > When I tried to run agentofdeath test from [1], snmpd daemon will crash > | > with malloc(): smallbin double linked list corrupted or double free() > issue > | > and dumps core (see bellow). > | > From log file, I can identified one issue with "Unknown operation". > | > > | > This issue is in the agentx_got_response function > | > (agent/mibgroup/agentx/master.c). There isn't implemented action for > | > NETSNMP_CALLBACK_OP_RESEND (defined in > | > include/net-snmp/library/snmp_api.h). > | > As result "Unknown operation 6 in agentx_got_response" is shown in log > | > file. > | > > | > /var/log/messages > | > ------------------------------- > | > Mar 28 06:52:42 localhost snmpd[12073]: Unknown operation 6 in > | > agentx_got_response > | > Mar 28 06:52:43 localhost snmpd[12073]: Unknown operation 6 in > | > agentx_got_response > | > Mar 28 06:52:43 localhost snmpd[12073]: malloc(): smallbin double > linked > | > list corrupted > | > Mar 28 06:52:43 localhost systemd[1]: Started Process Core Dump (PID > | > 13652/UID 0). > | > Mar 28 06:52:48 localhost systemd[1]: snmpd.service: Main process > exited, > | > code=dumped, status=6/ABRT > | > Mar 28 06:52:48 localhost systemd[1]: snmpd.service: Failed with result > | > 'core-dump'. > | > ------------------------------- > | > > | > The "Unknown operation" callback is caused by newly added piece of > code in > | > snmplib/snmp_api.c: > | > > | > static int > | > snmp_resend_request(struct session_list *slp, netsnmp_request_list > *rp, > | > int incr_retries) > | > { > | > > | > ... > | > > | > tv.tv_sec += tv.tv_usec / 1000000L; > | > tv.tv_usec %= 1000000L; > | > rp->expireM = tv; > | > + if (rp->callback) > | > + rp->callback(NETSNMP_CALLBACK_OP_RESEND, sp, > | > + rp->pdu->reqid, rp->pdu, rp->cb_data); > | > } > | > return 0; > | > } > | > > | > > | > When I tried to remove it, it just stop complaining about operation 6, > but > | > the core dump is still present. > | > > | > May I ask you for help with this issue? Do you have any idea, what > causing > | > this issue in 5.8 and how to fix it? > | > I know, that Jan Safranek has fixed this for 5.7 by commit [2], but it > | > looks like something other has changed and this issue is current again. > | > > | > [1] https://sourceforge.net/p/net-snmp/bugs/2411/ > | > [2] > | > > https://github.com/net-snmp/net-snmp/commit/793d596838ff7cb48a73b675d62897c56c9e62df > | > > | > Regards > | > > | > Josef Ridky > | > Software Engineer > | > Core Services Team > | > Red Hat Czech, s.r.o. > | > > | > > | > > | > _______________________________________________ > | > Net-snmp-coders mailing list > | > Net-snmp-coders@lists.sourceforge.net > | > https://lists.sourceforge.net/lists/listinfo/net-snmp-coders > | > > | >
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