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

Subject: Bug in sequencer, V2.0.10 and earlier
From: "Allison, Stephanie" <[email protected]>
To: "EPICS Tech-Talk" <[email protected]>
Date: Mon, 25 Jul 2005 15:30:33 -0700
Hello -

There is a bug in the sequencer, version 2.0.10 and earlier, seq/src/seq/seq_ca.c.  A pointer is being copied when a memory copy should be done instead.   For an RTEMS IOC, it causes a crash.  This bug is seen only if you happen to BOTH monitor and get a PV on another IOC and that other IOC is rebooted.  The second reboot of the other IOC after the sequence started causes the crash of the IOC running the sequence.  This is a very unusual situation.  The only reason we saw it is that we were upgrading device support to add db_post_event on a field and temporarily doing both gets and monitors until all IOCs could be rebooted.

Thanks to Till Straumann who used his RTEMS debugger to get a helpful stack trace.

Can someone add this fix to the next sequencer release?

The fix:

cvs diff -r SEQ-2-0-10
cvs diff: Diffing .
Index: seq_ca.c
===================================================================
RCS file: /afs/slac/g/lcls/cvs/epics/site/src/seq/src/seq/seq_ca.c,v
retrieving revision 1.1.1.1
retrieving revision 1.2
diff -r1.1.1.1 -r1.2
230c230,233
<           pDB->message = pvVarGetMess(pDB->pvid);
---
>             if (pvVarGetMess(pDB->pvid))
>                 pDB->message = Strdcpy(pDB->message, pvVarGetMess(pDB->pvid));
>             else
>                 pDB->message = Strdcpy(pDB->message, "unknown");

Thank you,

Stephanie Allison
SLAC/SSRL, SLAC/LCLS


Replies:
Re: Bug in sequencer, V2.0.10 and earlier Andrew Johnson

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