Thread: Segmentation Fault

When I run this program I get segmentation fault.The code compiles and runs till the last line but when it encounters the "free()" commands in the last lines in main, it gives segmentation fault. when i comment the free command, the code runs normal.

Code:

int main()
{
   double *weig;
   tm tyme;
   mdl model;
   int numWeig = 2,ctr=0;
   int i,j,ii,k,npts;
   double *MM, *NN,*MMtmp,*MMtmp2;
   double *xint1,*xint2,*wint1,*wint2;
   double value;
   double temp1[DIMENSION];
   double temp2[DIMENSION];
   double Pk[NUMWEIG];
   double Lk[NUMWEIG];
   double mutmp[NUMWEIG][DIMENSION];
   double numOfPoints = 1;
   struct timeval tm;
   time_t ts ,te;
   double tdiff;
   double sig1[2][3][3];
   double sig2[2][3][3];
   model.fn = 3;
   tyme.dt = 0.01;
   npts = POINTS;
   ts = 0;te = 0;

   MM = (double *)malloc(numWeig*numWeig*sizeof(int));
   NN = (double *)malloc(numWeig*numWeig*sizeof(int));

   for(i = 0;i < NUMWEIG;i++)
   {
      for(j = 0;j<NUMWEIG;j++)
      {
         *(MM+i*NUMWEIG+j) = 0;
      }
   }
   MMtmp = MM;
   MMtmp2 = MM;
   double sigtmp[2][3][3];
   double sig[2][3][3]={{{38.4276,50.4741,0.7706},{50.4741,66.7545,0.6300},{0.7706,0.6300,0.7731}},
                            {{36.1442,46.9353,-0.6776},{46.9353,61.4765,-0.3843},{-0.6776,-0.3843,0.9562}}};
   double mu[2][3] = {{2.5898,3.3019,21.4641}, {-2.5898,-3.3019,21.4641}};
   for(i = 0;i<model.fn;i++)
   {
      numOfPoints = numOfPoints*npts;
   }
   xint1 = (double *)malloc(numOfPoints*model.fn*sizeof(double));
   xint2 = (double *)malloc(numOfPoints*model.fn*sizeof(double));
   wint1 = (double *)malloc(numOfPoints*sizeof(double));
   wint2 = (double *)malloc(numOfPoints*sizeof(double));

   ts = clock();
   for(i = 0,ii = i+1;i<numWeig,ii<numWeig;i++,ii++)
   {
      for(j = 0;j < model.fn;j++)
      {
         for(k = 0;k < model.fn; k++)
         {
           sigtmp[i][j][k] = sig[i][j][k]+sig[ii][j][k];
           mutmp[i][k] = mu[i][k] - mu[ii][k];
         }
      }
   }

   for(i = 0;i<numWeig;i++)
   {
      for(j = 0;j < model.fn;j++)
      {
         for(k = 0;k < model.fn; k++)
         {
           sig1[i][j][k] = sig[i][j][k];
           sig2[i][j][k] = sig[i][j][k];
         }
      }
   }
   for(i = 0;i < numWeig;i++)
   {
      for(j = i+1;j < numWeig;j++)
      {
         *(MMtmp+i*numWeig+j) = getlikelHood(mutmp[i],&sigtmp[i][0][0]);
      }

      if(chckdgnl(&sig1[i][0][0],model.fn)==0)
         value=0;
      else
         value=deter(&sig1[i][0][0],model.fn);

      *(MM+i*NUMWEIG+i) = (double)(1/sqrt(16*pi*pi*pi*value));
   }
   for(i = 0;i<numWeig;i++)
   {
      for(j = 0;j<numWeig;j++)
      {
         *(MM+i*numWeig+j) = (double)(*(MM+i*numWeig+j)+*(MMtmp+i*numWeig+j)+*(MMtmp+j*numWeig+i))/(tyme.dt*tyme.dt);
      }
   }
   GenerateQuadPoints(&sig2[0][0][0],mu[0],npts,model.fn,xint1,wint1);
   GenerateQuadPoints(&sig2[1][0][0],mu[1],npts,model.fn,xint2,wint2);

   for(ctr = 0; ctr<numOfPoints; ctr++)
   {
      for(j=0;j<DIMENSION;j++)
      {
         temp1[j] = *((xint1)+j+ctr*DIMENSION);
         temp2[j] = *((xint2)+j+ctr*DIMENSION);
      }
      ComputeErrCoeff_QP(temp1,temp2,*(wint1+ctr),*(wint2+ctr),mu,&sig[0][0][0],DIMENSION,tyme.dt,Pk,Lk);      
      printf("\nIteration Number = %d\n",ctr);
      for(i = 0;i<numWeig;i++)
      { 
         for(j = 0;j<numWeig;j++)
         {
            *(NN+i*numWeig+j)= *(NN+i*numWeig+j)+Pk[i]*Lk[j];
         }
      }
   }
   te = clock();
   tdiff = te-ts;
   printf("\ntime elapsed = %f",(double)(te-ts));
   for(i = 0;i<2;i++)
   {
      printf("\n");
      for(j = 0;j<2;j++)
      {
         printf("\t%f",*(NN+i*2+j));
      }
   }
   printf("\n");
   free(NN);
   free(MM);
   free(xint1);
   free(xint2);
   free(wint1);
   free(wint2);
   return 0;
}

You've probably overlaid something. Which free() is failing?

If a crash is occurring in free(), the usual cause is some preceding code (and, no, that doesn't just mean the corresponding malloc() call) has tromped an invalid area of memory, and happened to tromp on data structures used internally by malloc()/free/ etc.

Given that a several sections of your code are working with arrays (or pointers that act on arrays), and the logic is not exactly straight-forward, I'd look there. Plenty of opportunity for mucking up an index, and walking off the end of an arrays.

You also seem to have macros and variables representing the same thing (eg a macro named NUMWEIG - which isn't actually defined - and a variable named numWeig). If you have a mismatch between those, they may also cause some of your loops to fall off the end of arrays.

stahta01 is correct, the allocation sizes are way off.