Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Wed, 5 Sep 2018 14:02:44 +0000

Hi Pilar,

I think your case is different from the tech-talk thread.  In the tech-talk thread they said there was no IOC error mesage, but in  your case you have a very clear IOC error message:

> epicsStrDup: mallocMustSucceed(1) - malloc failed Thread scan2 (0x9c2b038) suspending.

This says to me that your IOC has run out of memory.  I suspect there is a memory leak somewhere.

Is this a 32 or 64 bit machine, and how much memory does it have?

You could restart the IOC and use "top" to look at the memory usage with time.

What version of EPICS are you using, and what devices does this IOC control?

Mark

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Pilar Gil Jaldo
Sent: Wednesday, September 5, 2018 8:36 AM
To: [email protected]
Subject: Linux scan thread suspended

Hello everybody,

I have a question regarding the reasons why a scan thread can be suspended. I have a running IOC and at a certain moment the IOC breaks with following message:

epicsStrDup: mallocMustSucceed(1) - malloc failed Thread scan2 (0x9c2b038) suspending.

I have found in the tech-talk messages following reason which seems to be the same problem that mine.

https://epics.anl.gov/tech-talk/2013/msg00154.php

The IOC is on a network where many devices are sending packages to the CA network, but nobody is answering because other devices are switched off (the traffic in the CA is very high).

Is it possible that the segmentation fault is caused by a network congestion? Can the scan thread be suspended by a higher network traffic?

Thank you very much in advance for your answers.
Pilar Gil Jaldo

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System