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Subject: Error that seems to suspend all .st programs
From: "McClanahan, Ryan via Tech-talk" <[email protected]>
To: "[email protected]" <[email protected]>
Date: Wed, 3 Dec 2025 18:26:01 +0000
Hi,

I get the following error from time to time in a soft IOC that only hosts a few .st programs, and each time I get the message all of the .st programs lock up.  This must be something deep in epics because I don't have a seq_ca.c in my app, and it asks me to email teck-talk.  What can I do about this?

A call to 'assert(dbch)'
    by thread 'CAC-TCP-recv' failed in ../seq_ca.c line 378.
Dumping a stack trace of thread 'CAC-TCP-recv':
[          0x777ac3]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(epicsStackTrace+0x53)
[          0x77207e]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(epicsAssert+0x3e)
[          0x533a0b]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(seq_camonitor+0x14b)
[          0x533bbb]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(seq_conn_handler+0x17b)
[          0x73b4df]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(_ZN16oldChannelNotify13connectNotifyER10epicsGuardI10epicsMutexE+0x3f)
[          0x73fdc5]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(_ZN3cac23createChannelRespActionER15callbackManagerR6tcpiiuRK9epicsTimeRK15caHdrLargeA
rrayPv+0xc5)  
[          0x74cad3]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(_ZN6tcpiiu15processIncomingERK9epicsTimeR15callbackManager+0x1e3)
[          0x74ecd7]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(_ZN13tcpRecvThread3runEv+0x267)
[          0x76dc9b]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(epicsThreadCallEntryPoint+0x2b)
[          0x7731b2]: /afs/slac/g/lcls/epics/iocCommon/sioc-sys0-ts06/iocSpecificRelease/bin/rhel9-x86_64/tpgSupport(start_routine+0xc2)
[    0x7fb4a8c89d22]: /lib64/libc.so.6(start_thread+0x2d2)
[    0x7fb4a8d0ed40]: /lib64/libc.so.6(__clone3+0x30)
EPICS Release EPICS R7.0.3.1-1.0.6.
Local time is 2025-11-26 17:23:41.758220473 PST
Please E-mail this message to [email protected] or to [email protected]
Calling epicsThreadSuspendSelf()


sioc-sys0-ts06>seqShow bsaControl23
State Program: "bsaControl"
  thread priority = 50
  number of state sets = 1
  number of syncQ queues = 0
  number of channels = 20016
  number of channels assigned = 852
  number of channels connected = 192
  number of channels monitored = 4
  options: async=0, debug=1, newef=1, reent=1, conn=1
  user variables: address = 0x7fb45987a010, length = 960336

  State Set: "bsaControlss"
  thread name = bsaControl23;  Thread id = 0x58ee1f0
  First state = "new_root_names"
  Current state = "checking"
  Previous state = "assigning"
  Elapsed time since state was entered = 578695.89 seconds
  Wake up delay = inf seconds
  Get in progress = [000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000]
  Put in progress = [000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000]

Kind Regards,

Ryan McClanahan

AD-EED Controls Software

Desk Ext. 7493

SLAC National Laboratory
Bldg 034, Rm 206

2575 Sand Hill Rd., MS50
Menlo Park, CA. 94025


Replies:
Re: Error that seems to suspend all .st programs Michael Davidsaver via Tech-talk

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