Experimental Physics and
Industrial Control System

Hi Mark,
I believe Jakub just uses Visual Studio Code as an IDE environment, and still uses GCC toolchain to compile everything.

Jakub,
To simply the problem, it would be better to run the application from command line without the IDE, in this case, Visual Studio Code.
You can capture the seg fault core dump, and get the stack trace from gdb which Mark asked for.

Thanks,
Guobao

On 1/18/19, 3:23 PM, "[email protected] on behalf of Mark Rivers via Tech-talk" <[email protected] on behalf of [email protected]> wrote:

    I don’t know anything about Visual Studio Code, sorry.
   
    Can I ask why you are not using the gcc compiler and Linux vendor library if you are running on Linux?
   
    Mark
   
   
    Sent from my iPhone
   
    On Jan 18, 2019, at 10:03 PM, Wlodek, Jakub <[email protected]<mailto:[email protected]>> wrote:
   
   
    Hi Mark,
   
   
    I'm actually running the camera on a Debian 9 machine with Visual Studio Code, which does not have the breadth of debugging features found in standard Visual Studio. I believe Visual Studio is Windows only so I'm not sure if I will be able to get that stack. In VS Code the debugger only allows you to debug a program line by line but doesn't have any output other than a list of active program threads and the terminal to the best of my knowledge.
   
   
    Is there another way I could get the call stack?
   
   
    Jakub
   
    ________________________________
    From: Mark Rivers <[email protected]<mailto:[email protected]>>
    Sent: Friday, January 18, 2019 3:27:41 PM
    To: Wlodek, Jakub
    Cc: [email protected]<mailto:[email protected]>
    Subject: Re: Segmentation Fault when exiting certain Area Detector IOCs
   
    Hi Jakob,
   
    That is not what I meant by a stack trace. I meant the call stack shown in the Visual Studio debugger, showing which calls led up to the call to pPvt->lock().
   
    Mark
   
   
    Sent from my iPhone
   
    On Jan 18, 2019, at 7:15 PM, Wlodek, Jakub <[email protected]<mailto:[email protected]><mailto:[email protected]>> wrote:
   
   
    Hi Mark,
   
   
    Here is the stack trace from the call when exiting from the prosilica camera I have been using (With all debugging masks turned on):
   
    epics> exit
    Disconnecting camera CAM
    2019/01/18 13:14:14.101 [CAM,-1,0] [../prosilica.cpp:1235] [_main_,0x563326a1f060,0] prosilica:disconnectCamera: disconnecting camera 105850
    2019/01/18 13:14:14.101 [CAM,-1,0] [../../asyn/asynRecord/asynRecord.c:905] [_main_,0x563326a1f060,0] XF:10IDC-BI{GC1380-Cam:1}cam1:AsynIO: exception 0, asynExceptionConnect
    2019/01/18 13:14:14.101 [CAM,-1,0] [../prosilica.cpp:1262] [_main_,0x563326a1f060,0] prosilica:disconnectCamera: Camera disconnected; unique id: 105850
    Uninitializing PvAPI
    prosilicaApp: abort due to signal 11 (SIGSEGV) "Segmentation Fault"...
    Aborted
   
   
    When I exit from the driver I've written, I get the following:
   
    epics> exit
    ./startEPICS.sh: line 3: 30814 Segmentation fault      (core dumped) ../../bin/linux-x86_64/adUVCApp st.cmd
   
   
    In both cases the SegFault seems to happen every time I exit from this IOC, and in both cases I can trace it to the pPvt->lock(); line.
   
    As for the versions,
    ADCore 3.4.0
    ADProsilica 2.5.0
    asyn 4.34
   
    These should all be the most recent versions, as they were all pulled and compiled from Github on Wednesday, but I have seen this issue with this camera on earlier versions as well.
   
    Thanks for the help,
    Jakub
   
   
   
    ________________________________
    From: Mark Rivers <[email protected]<mailto:[email protected]><mailto:[email protected]>>
    Sent: Friday, January 18, 2019 12:31:13 PM
    To: Wlodek, Jakub
    Cc: [email protected]<mailto:[email protected]><mailto:[email protected]>
    Subject: Re: Segmentation Fault when exiting certain Area Detector IOCs
   
    Also please tell me what versions of asyn, ADCore, and ADProsilica you are using.
   
   
    Mark
   
   
   
    ________________________________
    From: [email protected]<mailto:[email protected]><mailto:[email protected]> <[email protected]<mailto:[email protected]><mailto:[email protected]>> on behalf of Mark Rivers via Tech-talk <[email protected]<mailto:[email protected]><mailto:[email protected]>>
    Sent: Friday, January 18, 2019 11:26 AM
    To: Wlodek, Jakub
    Cc: [email protected]<mailto:[email protected]><mailto:[email protected]>
    Subject: Re: Segmentation Fault when exiting certain Area Detector IOCs
   
    Hi Jacob,
   
   
    > Segmentation Fault: line of st.cmd file that calls ioc binary.
   
   
    Does this happen every time you exit the IOC, or only occasionally?
   
   
    I just tested a ADProsilica on Linux several times and I don't get this error, I see the following:
   
   
    epics> exit
   
    Disconnecting camera PS1
   
    Uninitializing PvAPI
   
   
    > and it occurs in the line pPvt->lock(), meaning that most likely pPvt is NULL.
   
    > Is there anything I should check for that could be causing this?
   
   
    I suspect that what is happening is that the asynPortDriver destructor has been called, so asynPortDriver::mutexId has been destroyed.   That causes pPvt->lock() to seg fault.  The question is why the connect() method is being called after the destructor has been called.  This seems like things are not shutting down in the correct order.  Can you send a more complete stack trace when the error occurs so we can see where connect() is being called from?
   
   
    Mark
   
   
   
    ________________________________
    From: [email protected]<mailto:[email protected]><mailto:[email protected]> <[email protected]<mailto:[email protected]><mailto:[email protected]>> on behalf of Wlodek, Jakub via Tech-talk <[email protected]<mailto:[email protected]><mailto:[email protected]>>
    Sent: Friday, January 18, 2019 10:35 AM
    To: [email protected]<mailto:[email protected]><mailto:[email protected]>
    Subject: Segmentation Fault when exiting certain Area Detector IOCs
   
   
    Hello EPICS Tech-Talk!
   
   
    I have a question regarding a segmentation fault I am getting when exiting certain area detector IOCs. Thus far, I have noticed it on several detectors, including a prosilica IOC and a new driver I have developed for USB Video Class cameras. In the IOC shell, the only information given is:
   
   
    Segmentation Fault: line of st.cmd file that calls ioc binary.
   
   
    Using the Visual Studio Code debugger I was able to trace the segmentation fault to the following function in the asynPortDriver.cpp file:
   
   
    extern "C" {static asynStatus connect(void *drvPvt, asynUser *pasynUser)
    {
        asynPortDriver *pPvt = (asynPortDriver *)drvPvt;
        asynStatus status;
   
        pPvt->lock();
        status = pPvt->connect(pasynUser);
        pPvt->unlock();
        return(status);
    }}
   
   
   
    and it occurs in the line pPvt->lock(), meaning that most likely pPvt is NULL. Is there anything I should check for that could be causing this?
   
   
    Thank you all in advance,
   
   
    Jakub Wlodek