Experimental Physics and
Industrial Control System

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] <[email protected]> on behalf of Wlodek, Jakub via Tech-talk <[email protected]>
Sent: Friday, January 18, 2019 10:35 AM
To: [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

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Re: Segmentation Fault when exiting certain Area Detector IOCs Mark Rivers via Tech-talk

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Segmentation Fault when exiting certain Area Detector IOCs Wlodek, Jakub via Tech-talk

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