I tried adding this inside the brk system call function :

```
void *addr = sbrk(0);
printk("current-add-is-%p-\n", addr);

```

But it returned error during kernel compilation that implicit declaration of sbrk function. And I could not find where sbrk is defined!!
All I need to measure that whenever some user process tries to extended its program break address, I would know its current program break address, so that I can measure how much memory processes are requesting.

Thank you.