Experimental Physics and
Industrial Control System

"Kasemir, Kay" <[email protected]> · Fri, 09 Jul 2010 08:47:01 -0400

Hi:

At the SNS we're using a version of vxStats where devVxStats.c looks similar
to this synapps release:
https://subversion.xor.aps.anl.gov/trac/synApps/browser/vxStats/trunk/vxStat
sApp/src/devVxStats.c

The cluster info support in there seems to cause memory corruption.

clustinfo is defined like this for 10 elements
974    #define CLUSTSIZES 10
975    
976    static int clustinfo[2][CLUSTSIZES][4];

... but later filled for CL_TBL_SIZE elements:
997    void getClusts(int dataPool)
998    {
999       NET_POOL_ID pNetPool;
1000       int i;
1001       int test;
1002    
1003       if (dataPool)
1004       {
1005          dataPool = 1;
1006          pNetPool = _pNetSysPool;
1007       }
1008       else
1009       {
1010          pNetPool = _pNetDpool;
1011       }
1012    
1013       test = pNetPool->clTbl[0]->clSize;
1014       for (i = 0; i < CL_TBL_SIZE; i++)
1015       {
1016          /* first two are constant under current conditions and could
be
1017           * done just once per pool.
1018           */
1019          if (i > 0)
1020             if (pNetPool->clTbl[i]->clSize != (2 * test)) break;
1021          test = pNetPool->clTbl[i]->clSize;
1022          clustinfo[dataPool][i][0] = test;
1023          clustinfo[dataPool][i][1] = pNetPool->clTbl[i]->clNum;
1024          clustinfo[dataPool][i][2] = pNetPool->clTbl[i]->clNumFree;
1025          clustinfo[dataPool][i][3] = pNetPool->clTbl[i]->clUsage;
1026       }
1027    }

On our MV2100 CPUs, CL_TBL_SIZE evaluates to 11, which might be close
enough. With our new MV5500 setups, CL_TBL_SIZE is 16, which in one case
happened to cause getClusts() to clobber a save_restore structure.

Replacing all use of CLUSTSIZES with CL_TBL_SIZE fixes the issue.
We also changed 

980    void minMBuf(int dataPool, int *ret)
981    {
982       int i;
983       double lowest = 1.0, comp;
984    
985       i = 0;
986       dataPool = dataPool?1:0;
987       while (clustinfo[dataPool][i][0] != 0)

into

987       while (i < CL_TBL_SIZE   &&   clustinfo[dataPool][i][0] != 0)

Thanks,
Kay

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System