Messages in this thread | | | Subject | Re: [patch 5/8] hrtimer remove state field | From | Thomas Gleixner <> | Date | Sun, 12 Mar 2006 14:35:05 +0100 |
| |
Roman,
I looked up the exact problem again.
On Sun, 2006-03-12 at 14:26 +0100, Roman Zippel wrote: > > softirq runs on CPU0 > > base->lock() > > > > remove_timer(timer); > > > > base->unlock() > > signal of previous expiry is delivered on CPU1 > > timer is reqeued.
-------> sig_ignore is set
> > requeue = timer->fn(); > > > > base->lock() > > > > if (requeue) > > enqueue_timer(timer) > > > > --> OOPS > > > > We can not wait in the signal delivery path until the callback has been > > executed, as we hold the posix-timer->lock and this would deadlock > > timer->fn(). > > posix_timer either restarts the timer directly or via signal delivery, but > never both, so this case can't happen (unless there is a bug in the > posix_timer).
It took quite a time to track this down. Its unlikely, but it _CAN_ happen !
tglx
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |