* Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > On 09/01, Ingo Molnar wrote: > > > > * Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > > > > But I must admit, now I don't understand what happens, > > > > > > The modification of that variable is protected by the BKL, but > > > the _ordering_ of the initial task (which becomes the idle > > > thread of CPU0) and the init task (which is spawned by the > > > initial task) is not synchronized. > > > > > > So we can occasionally end up init running sooner than > > > rest_init() > > > > > > How? rest_init() can't be preempted and it holds BKL. And > > > kernel_init() takes BKL before anything else. Confused... > > > > it cannot be preempted but it can schedule anywhere - and the BKL > > will be dropped silently. > > > > This is one of the biggest dangers of the BKL > > Yes I see. But rest_init() runs under preempt_disable(). If it was > rescheduled, schedule_debug() should complain. No? hm, either something is broken, or some other codepath learned to do preempt_enable() in early init ... [which i'd call broken too] Weird. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|