On Sun, 2005-03-20 at 07:36 +0100, Manfred Spraul wrote: > cpu 1: > acquire random networking spin_lock_bh() > > cpu 2: > read_lock(&tasklist_lock) from process context > interrupt. softirq. within softirq: try to acquire the networking lock. > * spins. > > cpu 1: > hardware interrupt > within hw interrupt: signal delivery. tries to acquire tasklist_lock. > > --> deadlock.
Signal delivery from hw interrupt context (interrupt is flagged SA_NODELAY) is not possible in RT preemption mode. The local_irq_save_nort() check in __cache_alloc will catch you. When it happens from a threaded irq handler the situation is solvable by the PI code. tglx - 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/
