On Fri, 18 Jan 2008, Jan Kiszka wrote: > Steven Rostedt wrote: > .... > > @@ -978,7 +980,13 @@ void release_console_sem(void) > > console_locked = 0; > > up(&console_sem); > > Hmm, just looking at this fragment: Doesn't up() include the risk of > running onto the runqueue lock as well?
Very little risk (if any). If printk fails to get the console_sem it doesn't block. So there would be no waiters on the semaphore, and thus try_to_wake_up would not be called. The only place I see the down actually being called is in suspend code, and even then, we would need to lock the rq of the task that is trying to grab the console_sem and the deadlock would only occur if that was on the same CPU. And honestly, I'm not sure that's even possible. -- Steve > > > spin_unlock_irqrestore(&logbuf_lock, flags); > > - if (wake_klogd) > > + /* > > + * If we try to wake up klogd while printing with the runqueue lock > > + * held, this will deadlock. We don't have access to the runqueue > > + * lock from here, but just checking for interrupts disabled > > + * should be enough. > > + */ > > + if (!irqs_disabled() && wake_klogd) > > wake_up_klogd(); > > } > > EXPORT_SYMBOL(release_console_sem); > > Jan > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
