2007/6/5, Attilio Rao <[EMAIL PROTECTED]>:
2007/6/5, Bruce Evans <[EMAIL PROTECTED]>:
>
> I get a "spin lock held too long" panic during (an interrupt in?) acpi
> initialization on booting non-PREEMPTION SCHED_4BSD SMP. Haven't tried
> other cases.
Do you have a backtrace or any other debugging stuffs available?
Mmm, I think I got the bug.
basically, in kern_mutex.c::_mtx_unlock_sleep(), in the not-preemptive
case what happens at some point is:
td = curthread;
if (td->td_critnest > 0 || td1->td_priority >= td->td_priority)
return;
thread_lock(td1);
if (!TD_IS_RUNNING(td1)) {
...
mi_switch(SW_INVOL, NULL);
...
}
thread_unlock(td1);
Which is wrong beacause td1 is not curthread and really curthread
should be locked too when context switching.
To a first look the idea is that td and td1 should be locked both, but
I just want more time to look better at it.
Attilio
--
Peace can only be achieved by understanding - A. Einstein
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