bug and fix in iocCore

[Dirk Zimoch <dirk.zimoch@psi.ch>]

Hi all,

at least on all EPICS releases 3.13.2 to 3.13.9, is a bug that causes 
crashes on PPC iocs. (I have not seen a 68k crash here.)

Bug:

When reading the DTYP field of "pure soft records" such as calc via CA, 
the CA_client task crashes and leaves the ioc in a state where no 
further access via CA is possible.

data access
Exception current instruction address: 0x01705f54
Machine Status Register: 0x0000b030
Data Access Register: 0xf0f0f0f0
Condition Register: 0x28000040
Data storage interrupt Register: 0x40000000
Task: 0x17c31f0 "CA_client"

> tt
17807c vxTaskEntry    +60 : camsgtask ()
1727a44 camsgtask      +2e4: camessage ()
172a7f0 camessage      +120: read_action ()
17286bc read_action    +e8 : read_reply ()
17284b4 read_reply     +144: db_get_field ()
171f838 .L198          +40 : dbGetField ()
1707650 dbGetField     +164: dbGet ()
1707760 dbGet          +cc : getOptions ()
17065d8 getOptions     +208: get_enum_strs ()

Fix:

*** base/src/db/dbAccess.c.orig Thu Jun  3 18:04:26 2004
--- base/src/db/dbAccess.c      Thu Jun  3 18:10:33 2004
***************
*** 129,134 ****
--- 129,138 ----
                    goto choice_common;
                case DBF_DEVICE:
                    pdbDeviceMenu = (dbDeviceMenu *)pdbFldDes->ftPvt;
+                   if (pdbDeviceMenu == NULL) {
+                       no_str = 0;
+                       goto choice_common;
+                   }
                    no_str = pdbDeviceMenu->nChoice;
                    papChoice = pdbDeviceMenu->papChoice;
                    goto choice_common;


After this fix, calc records and the like report DTYP as 0.

Dirk

--
Dr. Dirk Zimoch
Swiss Light Source
Paul Scherrer Institut
Computing and Controls
phone +41 56 310 5182
fax   +41 56 310 4413