* Arne Jansen <lists@xxxxxxxxxxxxxx> wrote:
> From the timing I see I'd guess it has something to do with the
> scheduler kicking in during printk. I'm neither familiar with the
> printk code nor with the scheduler.
Yeah, that's the well-known wake-up of klogd:
void console_unlock(void)
{
...
up(&console_sem);
actually ... that's not the klogd wake-up at all (!). I so suck today
at bug analysis :-)
It's the console lock()/unlock() sequence, and guess what does it:
drivers/tty/tty_io.c: console_lock();
drivers/tty/vt/selection.c: console_lock();
and the vt.c code in a dozen places.
So maybe it's some sort of tty related memory corruption that was
made *visible* via the extra assert that the scheduler is doing? The
pi_list is embedded in task struct.
This would explain why only printk() triggers it and other wakeup
patterns not.
Now, i don't really like this theory either. Why is there no other
type of corruption? And exactly why did only the task_struct::pi_lock
field get corrupted while nearby fields not? Also, none of the fields
near pi_lock are even remotely tty related.
Thanks,
Ingo
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