nested loop error in OpenCL hardware run

Hello,

My openCL project produced wrong output in hardware run, and after several days debug, I finally found out the reason. The index in one of my nested loop structure is messed up and I really don't why this would ever happen. I have a nest loop structure like this:

****----------------------------------------------------------------------****

__kernel

void some_kernel() {

........

........

for (uint m = 0; m < m_bound; m++) {

for(uint n = 0; n < n_bound; n++) {

........

printf("m = %d, n = %d", m, n);

}

}

}

........

........

****-------------------------------------------------------------------------****

Of course the actual code is much more complicated than this simplified version. At the the beginning of this nested loop structure, m got incremented before n reaches its loop bound!! the output is like this:

****-------------------------------------------------------------------------****

m = 0, n = 0

m = 1, n = 0

m = 0, n = 1

m = 1, n = 1

m = 0, n = 2

m = 1, n = 2

.............

.............

****-----------------------------------------------------------------------****

And this only happens at the first few iterations(Only when m is 0 or 1). This is extremly weird, since in simulation it worked perfectly.

Any advice would be greatly appreciated!!

Best regards,

Lancer