Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Thu, 17 Feb 2011 15:48:25 -0800

As you mentioned, that error appears when there's a signal handler being run while a system call is active.   It appears that this message is coming from:

inBufClient::fillCondition
casDGIntfIO::osdRecv ( char * pBufIn, bufSizeT size, // X aCC 361
    fillParameter parm, bufSizeT & actualSize, caNetAddr & fromOut )
{
    int status;
    osiSocklen_t addrSize;
    sockaddr addr;
    SOCKET sockThisTime;

    if ( parm == fpUseBroadcastInterface ) {
        sockThisTime = this->bcastRecvSock;
    }
    else {
        sockThisTime = this->sock;
    }

    addrSize = ( osiSocklen_t ) sizeof ( addr );
    status = recvfrom ( sockThisTime, pBufIn, size, 0,
                       &addr, &addrSize );
    if ( status <= 0 ) {
        if ( status < 0 ) {
            if ( SOCKERRNO != SOCK_EWOULDBLOCK ) {
                char sockErrBuf[64];
                epicsSocketConvertErrnoToString ( sockErrBuf, sizeof ( sockErrBuf ) );
                errlogPrintf ( "CAS: UDP recv error was \"%s\"\n", sockErrBuf );
            }
        }
        return casFillNone;
    }

Jeff -- Is that SOCK_EWOULDBLOCK actually supposed to be SOCK_EINTR?  There's similar looking code in rsrv/cast_server.c:cast_server(void *pParm) that has 
SOCK_EINTR.

IMHO code that uses signals to get things done is inherently evil.....

On Feb 17, 2011, at 3:31 PM, Bruce Hill wrote:

> We're having a problem with 'CAS: UDP recv errors" that's causing
> our GigE camera IOC's to stop updating images overnight.
> 
> We're running EPICS 3.14.9, asyn R4.10.1, and areaDetector R1-2.
> 
> When the images stop, we get these errors on our console:
> 17_14:39:08:CAS: UDP recv error (errno=Interrupted system call)
> 17_14:39:08:CAS: UDP recv error (errno=Interrupted system call)
> 17_14:39:09:CAS: UDP recv error (errno=Interrupted system call)
> ...
> Googling "Interrupted system call" seems to indicated that repeating the
> system call, in this case, recv_from, may be needed.   It appears that the CA
> code is already doing that.
> 
> I'm hoping that Jeff or Mark, or anyone, may have already seen this problem.
> We've been working on upgrading to 3.14.11 and newer modules, so if this
> problem has already been fixed we may just need to refocus our efforts on
> the upgrade.
> 
> Thanks,
> - Bruce

-- 
Eric Norum
[email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System