Experimental Physics and
Industrial Control System

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<== Date ==>		<== Thread ==>

Subject:	RE: CAS-client thread issues in areaDetector IOC
From:	Mark Rivers via Tech-talk <[email protected]>
To:	"'Wlodek, Jakub'" <[email protected]>
Cc:	"[email protected]" <[email protected]>
Date:	Thu, 23 Jan 2020 17:06:41 +0000

Hi Jakub,

The errors are in the Channel Access server from EPICS base. Questions:

- Are your working cameras using the same version of base as the camera you are testing?

- Are you sure you have rebuilt everything that your camera IOC uses with this version of base?

This looks to me like it could be a memory corruption problem, e.g. array out of bounds. Those errors can remain hidden until you make small changes to your code.

I suggest running the IOC under valgrind to see if it detects memory allocation issues.

Mark

From: Tech-talk <[email protected]> On Behalf Of Wlodek, Jakub via Tech-talk
Sent: Thursday, January 23, 2020 9:44 AM
To: [email protected]
Subject: CAS-client thread issues in areaDetector IOC

Hi all,

I am currently ironing out a few bugs in an areaDetector driver I wrote a while ago for USB webcams, and doing some code cleanup (removing redundant code etc.), and I have encountered an

error I have not seen before, and I'm not sure what I have done to introduce it. I have ~15 beamline cameras working with this driver for time frames ranging from several months to a year, so I am

fairly certain this is a new issue. Essentially, after the IOC runs normally for some time, I get the following stack trace dumped to the EPICS shell:

epicsEventTrigger: pthread_mutex_lock failed: Invalid argument

epicsEventMustTriggerThread CAS-client (0x7f4e4c042f00) can't proceed, suspending.

Dumping a stack trace of thread 'CAS-client':

[ 0x55bf0e032393]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(epicsStackTrace+0x73)

[ 0x55bf0e022dc5]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(cantProceed+0xc5)

[ 0x55bf0dfabfb3]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(db_close_events+0x33)

[ 0x55bf0dfd38df]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(destroy_tcp_client+0x8f)

[ 0x55bf0dfd44fd]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(camsgtask+0x13d)

[ 0x55bf0e02d7c8]: /epics/src/support/areaDetector/ADUVC/iocs/adUVCIOC/bin/linux-x86_64/adUVCApp(start_routine+0xf8)

[ 0x7f4f922c46db]: /lib/x86_64-linux-gnu/libpthread.so.0(start_thread+0xdb)

[ 0x7f4f9105988f]: /lib/x86_64-linux-gnu/libc.so.6(clone+0x3f)

Thread CAS-client (0x7f4e4c042f00) suspended

2020/01/23 10:28:32.930 ADUVC::acquireStop Stopping aquisition

2020/01/23 10:28:32.930 ADUVC::writeInt32 function=8 value=0

epicsEventTrigger: pthread_mutex_lock failed: Invalid argument

epicsEventMustTriggerThread CAS-client (0x7f4e4c0433d0) can't proceed, suspending.