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]>> 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]>>
Sent: Friday, January 18, 2019 12:31:13 PM
To: Wlodek, Jakub
Cc: [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]> <[email protected]<mailto:[email protected]>> on behalf of Mark Rivers via Tech-talk <[email protected]<mailto:[email protected]>>
Sent: Friday, January 18, 2019 11:26 AM
To: Wlodek, Jakub
Cc: [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]> <[email protected]<mailto:[email protected]>> on behalf of Wlodek, Jakub via Tech-talk <[email protected]<mailto:[email protected]>>
Sent: Friday, January 18, 2019 10:35 AM
To: [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