Experimental Physics and
Industrial Control System

Dirk Kraemer <[email protected]> · Mon, 20 Nov 2006 16:28:43 +0100

Eric Norum schrieb:

On Nov 20, 2006, at 5:50 AM, Dirk Kraemer wrote:
Hello all,
I have a problem with EDM. If I start EDM ,then
I see for a moment the message  "loading fonts" and a moment later
I get the message "segmentations fault".

I am running EDM on :
- Fedora 5 - gcc 4.1.0-3.i386
- Epics 3.14.8.2
- openMotif 2.3.0-0.1.9.i386
- edm 1-11-0s
I hope that someone can help me. It's the first time that I get this
fault.
Regards
Dirk Kraemer


Sounds suspiciously like the problem I encountered on OS X. Here's a
copy of the letter I sent to Jeff about this. Perhaps you're seeing
the same sort of condition, but with some other pair of static
constructors.
====================================================================================== 

I downloaded and built the latest version of edm with the current
R3.14.2 CVS branch of EPICS. Things build fine, but the executable
suffers an access fault when run. I tracked the problem down to a
race condition in the C++ static constructors. Code in
EPICS_PV_Factory is invoking a guard class mutex that has yet to be
set up.
Program received signal EXC_BAD_ACCESS, Could not access memory.

Reason: KERN_PROTECTION_FAILURE at address: 0x00000008

0x0008ae23 in epicsMutex::lock ()

(gdb) where

#0 0x0008ae23 in epicsMutex::lock ()

#1 0x00088e3a in ipAddrToAsciiEngine::allocate ()

#2 0x004aff0b in cac::cac ()

#3 0x004cfb5b in ca_client_context::ca_client_context ()

#4 0x004b25f4 in ca_context_create ()

#5 0x0041f4df in EPICS_PV_Factory::EPICS_PV_Factory ()

#6 0x0044cb2b in __static_initialization_and_destruction_0 ()

#7 0x8fe0fcb2 in
__dyld__ZN16ImageLoaderMachO16doInitializationERKN11ImageLoader11LinkContextE
()

#8 0x8fe0a1c6 in
__dyld__ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextE ()

#9 0x8fe0a164 in
__dyld__ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextE ()

#10 0x8fe0a164 in
__dyld__ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextE ()

#11 0x8fe0c646 in
__dyld__ZN11ImageLoader15runInitializersERKNS_11LinkContextE ()

#12 0x8fe03070 in __dyld__ZN4dyld24initializeMainExecutableEv ()

#13 0x0000245a in _start ()

#14 0x000023c5 in start ()


The offending code in misc/ipAddrToAsciiAsynchronous.cpp is:

// for now its probably sufficent to allocate one

// DNS transaction thread for all codes sharing

// the same process that need DNS services but we

// leave our options open for the future

ipAddrToAsciiEngine & ipAddrToAsciiEngine::allocate ()

{

epicsGuard < epicsMutex > guard (
ipAddrToAsciiEnginePrivate::globalMutex );

if ( ! ipAddrToAsciiEnginePrivate::pEngine ) {

ipAddrToAsciiEnginePrivate::pEngine = new
ipAddrToAsciiEnginePrivate ();

}

ipAddrToAsciiEnginePrivate::numberOfReferences++;

return * ipAddrToAsciiEnginePrivate::pEngine;

}


As a quick fix I just link libCom before the EDM libraries as well as
after:

diff -ur /home/phoebus/NORUME/Desktop/edm/edmMain/Makefile
/home/phoebus/NORUME/

src/EPICS/extensions/src/edm/edmMain/Makefile

--- /home/phoebus/NORUME/Desktop/edm/edmMain/Makefile 2006-03-06
13:25:32.0000

00000 -0600

+++
/home/phoebus/NORUME/src/EPICS/extensions/src/edm/edmMain/Makefile
2006-11-

14 13:12:30.000000000 -0600

@@ -10,7 +10,7 @@

edm_LIBS_Linux += 114135a4-6f6c-11d3-95bc-00104b8742df

edm_SYS_LIBS_Linux += Xm Xmu Xt Xp Xtst X11 pthread dl
-   edm_LIBS_Darwin += EdmBase cfcaa62e-8199-11d3-a77f-00104b8742df
+   edm_LIBS_Darwin += Com EdmBase cfcaa62e-8199-11d3-a77f-00104b8742df
    edm_LIBS_Darwin += 114135a4-6f6c-11d3-95bc-00104b8742df
    edm_SYS_LIBS_Darwin += Xm Xmu Xt Xp Xtst X11 pthread dl


I've sent mail to Jeff to see if he has a better fix, but for now I
can at least work with EDM.
--Eric Norum <[email protected]>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793
Hi
I have tried it with your changes, but the result is the same.
GNU gdb Red Hat Linux (6.3.0.0-1.122rh)
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There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu"...Using host
libthread_db library "/lib/libthread_db.so.1".
(gdb) run
Starting program: /home/Dirk/extensions/bin/linux-x86/edm
Reading symbols from shared object read from target memory...done.
Loaded system supplied DSO at 0x41cfd000
[Thread debugging using libthread_db enabled]
[New Thread -1208293152 (LWP 7736)]
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1208293152 (LWP 7736)]
0x00000000 in ?? ()
(gdb)
regards Dirk


Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System