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Subject: Re: Stream device does not recognize a custom record type
From: Dirk Zimoch <dirk.zimoch@psi.ch>
To: Abdalla Ahmad <abdalla.ahmad@sesame.org.jo>, "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Mon, 1 Oct 2018 10:58:46 +0200
Hi Abdalla,

I think I found your problem. You cannot use the mbbi2Record.h file generated with EPICS 3.14.12. You need to re-build it with the new EPICS base version. The reason is that this file is generated from your mbbi2.dbd file which includes dbCommon.dbd which may change from one EPICS version to another. That makes all the offsets of the fields wrong and accessing them using db functions like dbLoadLink results in wrong data being used. NULL pointer in your case.

Dirk

On 01.10.2018 09:44, Abdalla  Ahmad wrote:
Hello Dirk,

I think somehow stream device is involved, not that the problem is in it but how it interacts with this new record type. In the example PV I showed I changed the record type from mbbi2 to mbbiDirect and it works fine.

Regarding the stack trace there is something interesting. I looked up the mbbiDirect record source in base 3.15.5, specifically the file src/std/rec/mbbiDirectRecord.c and in the init_record routine (line 97), it first checks for a null device support entry table (struct mbbidset) before calling the function "recGblInitConstantLink". In the mbbi2 record this is inverted, it calls this function then checks for null pointer DSET. I re-arranged these two section to be the same as in the mbbi2Direct record and I got this on the IOC shell:

Missing device support entry table PV: BO-RF-SGN1:getStatusWord mbbi2: init_record

dbGetLinkValue: Illegal link type 1
Thread _main_ (0x8eb40e0) can't proceed, suspending.
Dumping a stack trace of thread '_main_':
[0x260bc4]: /home/control/epics/base-3.15.5/lib/linux-x86/libCom.so.3.15.5(epicsBackTrace+0x24)
[0x260a0e]: /home/control/epics/base-3.15.5/lib/linux-x86/libCom.so.3.15.5(epicsStackTrace+0x4e)
[0x24f420]: /home/control/epics/base-3.15.5/lib/linux-x86/libCom.so.3.15.5(cantProceed+0x50)
[0x17c532]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(dbGetLink+0xb2)
[0x16e61f]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(dbProcess+0x1af)
[0x1a4b5b]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(iocBuild_2+0x49b)
[0x1a4c0a]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(iocBuild+0x3a)
[0x1a4c77]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(iocInit+0x17)
[0x1a53f7]: /home/control/epics/base-3.15.5/lib/linux-x86/libdbCore.so.3.15.5(iocInitCallFunc+0x17)
[0x24a271]: /home/control/epics/base-3.15.5/lib/linux-x86/libCom.so.3.15.5(iocshBody+0xb41)
[0x24aa25]: /home/control/epics/base-3.15.5/lib/linux-x86/libCom.so.3.15.5(iocsh+0x25)
[0x804c54d]: ./bin/linux-x86/ioc(main+0x1d)
[0x29ace6]: /lib/libc.so.6(__libc_start_main+0xe6)
[0x804bb61]: ./bin/linux-x86/ioc(_start+0x21)

The record source code looks very similar to the standard mbbiDirect. I have checked structures' definitions, the EPICS export calls, record support routines, etc. in some other standard records. I'm not sure what I could be missing here.

Best Regards,
Abdalla.


-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Dirk Zimoch
Sent: Monday, October 01, 2018 10:10 AM
To: tech-talk@aps.anl.gov
Subject: Re: Stream device does not recognize a custom record type

Hello Abdalla,

In the stack trace you can see a problem with a NULL pointer access in your record support code. No StreamDevice involved here at all.

Are you sure you load the correct dbd file? Loading a dbd file of a wrong EPICS base version is a common cause for crashes.

I will try your code. Maybe I find something....

Dirk

On 30.09.2018 14:41, Abdalla  Ahmad wrote:
Hi

One of our IOC servers currently has the following setup:

OS: SL 6.4 32-bit

EPICS: 3.15.5 (previously 3.14.12.3)

synApps built from assemble_synApps script (previously 5.6)

Stream device R2-7-7a (Previously 2-5-1)

This IOC has some records that use a custom record called "mbbi2"
which was created here at SESAME by an engineer used to work here. The
purpose of this record is to provide alarm severity for each bit of
the standard mbbiDirect, otherwise they are the same.

The problem is integrating this record with the stream device driver.
What we found after searching the synApps 5.6 setup:

1.Adding MBBI2 definition to the stream device configure/RELEASE.

2.Including mbbi2.dbd and mbbi library in streamApp/Makefile.

3.Having mbbi2Record.h and devmbbiStream.c sources in the
StreamDevice/src

4.Adding mbbi2 to RECORDS in StreamDevice/src/CONFIG_STREAM

That's all under base 3.14.12.3, we are not sure if something else is
missing under 3.15.5 setup. With all these steps, the new stream
device driver compiles with mbbi2 definitions (dbd file, ldd command),
but when running the IOC it immediately crashes with segmentation
fault. I enabled core dumps, loaded the core dump into gdb, backtrace
it and I got this

Core was generated by `./bin/linux-x86/ioc iocBoot/ioc/st.cmd'.

Program terminated with signal 11, Segmentation fault.

#0  cvt_st_us (from=0xb <Address 0xb out of bounds>, to=0x87f9354,
paddr=0x0) at ../../../src/ioc/db/dbFastLinkConv.c:161

161     if (*from == 0) {

Missing separate debuginfos, use: debuginfo-install
glibc-2.12-1.107.el6_4.5.i686 libgcc-4.4.7-3.el6.i686
libstdc++-4.4.7-3.el6.i686 ncurses-libs-5.7-3.20090208.el6.i686
net-snmp-libs-5.5-44.el6_4.4.i686 openssl-1.0.0-27.el6_4.2.i686
pcre-7.8-6.el6.i686 readline-6.0-4.el6.i686 zlib-1.2.3-29.el6.i686

(gdb) backtrace

#0  cvt_st_us (from=0xb <Address 0xb out of bounds>, to=0x87f9354,
paddr=0x0) at ../../../src/ioc/db/dbFastLinkConv.c:161

#1  0x00848d0f in dbConstLoadLink (plink=0x87f9338, dbrType=4,
pbuffer=0x87f9354) at ../../../src/ioc/db/dbLink.c:108

#2  dbLoadLink (plink=0x87f9338, dbrType=4, pbuffer=0x87f9354) at
../../../src/ioc/db/dbLink.c:475

#3  0x008556fc in recGblInitConstantLink (plink=0x87f9338, dbftype=4,
pdest=0x87f9354) at ../../../src/ioc/db/recGbl.c:167

#4  0x006c14f8 in init_record (prec=0x87f91c0, pass=1) at
../mbbi2Record.c:153

#5  0x008719c7 in doInitRecord1 () at
../../../src/ioc/misc/iocInit.c:543

#6  iterateRecords () at ../../../src/ioc/misc/iocInit.c:472

#7  initDatabase () at ../../../src/ioc/misc/iocInit.c:551

#8  iocBuild_2 () at ../../../src/ioc/misc/iocInit.c:148

#9  0x00871c0a in iocBuild () at ../../../src/ioc/misc/iocInit.c:187

#10 0x00871c77 in iocInit () at ../../../src/ioc/misc/iocInit.c:99

#11 0x008723f7 in iocInitCallFunc (args=0x878ba80) at
../../../src/ioc/misc/miscIocRegister.c:25

#12 0x00a11271 in iocshBody (pathname=<value optimized out>,
commandLine=0x0, macros=0x0) at
../../../src/libCom/iocsh/iocsh.cpp:815

#13 0x00a11a25 in iocsh (pathname=0xbfe125f0 "iocBoot/ioc/st.cmd") at
../../../src/libCom/iocsh/iocsh.cpp:883

#14 0x0804c97d in main (argc=2, argv=0xbfe10514) at ../iocMain.cpp:17

The IOC was complaining about DTYP and BFST fields which it cannot set
their values, we looked up the mbbi2.dbd and found out deprecated
values for the promotgroup. We are not sure if this is the problem or
not but we changed all promotegroup to the new values found in base
3.15.5 app developer guide, the IOC accepted the DTYP field but still
unable to set . Still facing the same segmentation fault with the same backtrace.

Here is an example mbbi2 record:

record(mbbi2, "$(SYSTEM):getStatusWord")

{

      field(DESC, "Reads status word")

      field(SCAN, "2 second")

      field(DTYP, "stream")

      field(INP, "@work-microwave-ssx.proto getStatusWord
$(CONTROLLER)")

      field(VAL, "0")

      field(PINI, "YES")

      field(B0ST, "Standby mode")        field(B0ZSV, "NO_ALARM")
field(B0OSV, "NO_ALARM")

      field(B1ST, "PLO PLL")             field(B1ZSV, "NO_ALARM")
field(B1OSV, "MINOR")

      field(B2ST, "Reference PLL")       field(B2ZSV, "NO_ALARM")
field(B2OSV, "MAJOR")

      field(B3ST, "Reference PLL")       field(B3ZSV, "NO_ALARM")
field(B3OSV, "MINOR")

      field(B4ST, "Level Control")       field(B4ZSV, "NO_ALARM")
field(B4OSV, "NO_ALARM")

      field(B5ST, "MW")                  field(B5ZSV, "NO_ALARM")
field(B5OSV, "MINOR")

      field(B6ST, "OCXO/TCXO")           field(B6ZSV, "NO_ALARM")
field(B6OSV, "NO_ALARM")

      field(B7ST, "RF OFF")              field(B7ZSV, "NO_ALARM")
field(B7OSV, "NO_ALARM")

      field(B8ST, "Oven status (OCXO)")  field(B8ZSV, "NO_ALARM")
field(B8OSV, "NO_ALARM")

      field(B9ST, "Main synthesizer")    field(B9ZSV, "NO_ALARM")
field(B9OSV, "MAJOR")

      field(BAST, "VHF synthesizer")     field(BAZSV, "NO_ALARM")
field(BAOSV, "MAJOR")

      field(BBST, "Fine synthesizer")    field(BBZSV, "NO_ALARM")
field(BBOSV, "MAJOR")

      field(BCST, "DBLR-Status (SSX-3)") field(BCZSV, "NO_ALARM")
field(BCOSV, "MAJOR")

      field(BDST, "Summarized alarm")    field(BDZSV, "NO_ALARM")
field(BDOSV, "MAJOR")

      field(BEST, "Reference-PLL")       field(BEZSV, "NO_ALARM")
field(BEOSV, "MAJOR")

      field(BFST, "MW PLL")              field(BFZSV, "NO_ALARM")
field(BFOSV, "MAJOR")

}

Sorry for any misinformation, all our findings were the result of
comparing between the two EPICS bases and the two synApps collections.
Attached is the record's source code stream device interface files.

Best Regards,

Abdalla Ahmad

Control Engineer

SESAME

Allan, Jordan.

Tel: (+962-5) 3511348 , ext. 265

Fax: (+962-5) 3511423

Mob: (+962-7)88183296

www.sesame.org.jo <http://www.sesame.org.jo/>


Replies:
RE: Stream device does not recognize a custom record type Abdalla Ahmad
RE: Stream device does not recognize a custom record type Abdalla Ahmad
References:
Stream device does not recognize a custom record type Abdalla Ahmad
Re: Stream device does not recognize a custom record type Dirk Zimoch
RE: Stream device does not recognize a custom record type Abdalla Ahmad

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