Hi...
> I found that the kernel is preemptible and context switch happened.
Hm..ok...
> but printk() always print wrong msg,
> ex
> this is thread 1, loop 1
> this is thread 1, loop 2
> this is thread 2, loop 2000
"loop"? you print "loop"? I didn't see it in your code..CMIIW
> I don't know if printk has a buffer and will overflow in this situation.
> I used spinlock for this:
>
> spin_lock();
> printk("this is process %d\n",current->pid);
> spin_unlock();
>
> and everything looks fine.
hm, strange...what is the relation between printk(), pid and spin lock....
let's do it a bit different, how about this?
pid_t mypid;
mypid = current->pid;
printk("this is process %d\n",mypid);
does it work?
> without spin lock, something goes wrong, It looks someone disable
> interrupt and I tried to enable interrupt but it didn't work.
again....very strange. Your kernel thread PID should be static, right?
regards
Mulyadi
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