Question on Schedule and Preemption

["Liu haixiang" <liu.haixiang@gmail.com>]

Hi All,

Now I am developing the driver on Linux kernel 2.6.11. And I met the
problem that kernel will dump my stack from time to time. And the
kernel log will give me messages like "scheduling while atomic: ...".

Then I found the code in sched.c:

if (likely(!current->exit_state)) {
	if (unlikely(in_atomic())) {
		printk(KERN_ERR "scheduling while atomic: "
			"%s/0x%08x/%d\n",
			current->comm, preempt_count(), current->pid);
		dump_stack();
	}
}

Anybody can explain above code for me?

Thanks

best regards

Haixiang Liu