I use printf in my program to see local float variables. After 1 cycle of data, it hangs. It isn't killed by normal signals, and if I kill it with -KILL (9) it corrupts my display, at which point it crashes my PC.
If I comment out the printf statement, it runs normally through all 300 cycles.
printf("gid = %lu, gp = %p, avg = %f, avg = %f, avg = %f, avg = %f\n", f->me, gp, f->avg, f->avg, f->avg, f->avg);
I use sdk 3.0 in Ubuntu 14.04 and running my kernel from my R9 270 video card.