I'm writing code for calculating prefix sum. Here is my kernel

__global__ void prescan(int *indata,int *outdata,int n,long int *sums)  
{  
    extern __shared__ int temp[];  

    int tid=threadIdx.x;
    int offset=1,start_id,end_id;
    int *global_sum=&temp[n+2];

    if(tid==0)
    {
        temp[n]=blockDim.x*blockIdx.x;
        temp[n+1]=blockDim.x*(blockIdx.x+1)-1;
        start_id=temp[n];
        end_id=temp[n+1];
        //cuPrintf("Value of start %d and end %d\n",start_id,end_id);

    }
    __syncthreads();
    start_id=temp[n];
    end_id=temp[n+1];
    temp[tid]=indata[start_id+tid];
    temp[tid+1]=indata[start_id+tid+1];


    for(int d=n>>1;d>0;d>>=1)
    {
        __syncthreads();
        if(tid<d)
        {
            int ai=offset*(2*tid+1)-1;
            int bi=offset*(2*tid+2)-1;

            temp[bi]+=temp[ai];
        }
        offset*=2;
    }

    if(tid==0)
    {  
        sums[blockIdx.x]=temp[n-1];  
        temp[n-1]=0;
        cuPrintf("sums %d\n",sums[blockIdx.x]);
    }
    for(int d=1;d<n;d*=2)
    {
        offset>>=1;
        __syncthreads();
        if(tid<d)
        {
            int ai=offset*(2*tid+1)-1;
            int bi=offset*(2*tid+2)-1;
            int t=temp[ai];
            temp[ai]=temp[bi];
            temp[bi]+=t;
        }
    }

    __syncthreads();

    if(tid==0)
    {
        outdata[start_id]=0;
    }

    __threadfence_block();
    __syncthreads();
    outdata[start_id+tid]=temp[tid];
    outdata[start_id+tid+1]=temp[tid+1];
    __syncthreads();

    if(tid==0)  
    {  
        temp[0]=0;  
        outdata[start_id]=0;  

    }  

    __threadfence_block();
    __syncthreads();

    if(blockIdx.x==0 && threadIdx.x==0)
    {
        for(int i=1;i<gridDim.x;i++)
        {
            sums[i]=sums[i]+sums[i-1];
        }
    }

    __syncthreads();
    __threadfence();

    if(blockIdx.x==0 && threadIdx.x==0)
    {
        for(int i=0;i<gridDim.x;i++)
        {
            cuPrintf("****sums[%d]=%d ",i,sums[i]);
        }
    }


    __syncthreads();
    __threadfence();


    if(blockIdx.x!=gridDim.x-1)
    {
        int tid=(blockIdx.x+1)*blockDim.x+threadIdx.x;
        if(threadIdx.x==0)
            cuPrintf("Adding %d \n",sums[blockIdx.x]);
        outdata[tid]+=sums[blockIdx.x];

    }
    __syncthreads();

}

In above kernel, sums array will accumulate prefix sum per block and and then first thread will calculate prefix sum of this sum array. Now if I print this sum array from device side it'll show correct results while in

cuPrintf("Adding %d \n",sums[blockIdx.x]);

this line it prints that it is taking old value. What could be the reason?