Messages in this thread | | | Date | Wed, 7 Mar 2007 06:48:16 -0800 | From | Bill Irwin <> | Subject | Re: Wanted: simple, safe x86 stack overflow detection |
| |
On Tue, 2007-03-06 at 22:44 -0800, Bill Irwin wrote: >> What do you see as the obstacle to eliminating nested IRQ's?
On Wed, Mar 07, 2007 at 04:34:52AM -0800, Arjan van de Ven wrote: > political will, or maybe just the lack of convincing people so far
Political issues are significantly more difficult to resolve than technical ones.
On Tue, 2007-03-06 at 22:44 -0800, Bill Irwin wrote: >> It doesn't >> seem so far out to test for being on the interrupt stack and defer the >> call to do_IRQ() until after the currently-running instance of do_IRQ() >> has returned, or to move to per-irq stacks modulo special arrangements >> for the per-cpu IRQ's. Or did you have other methods in mind?
On Wed, Mar 07, 2007 at 04:34:52AM -0800, Arjan van de Ven wrote: > it's simpler... > irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) > { > irqreturn_t ret, retval = IRQ_NONE; > unsigned int status = 0; > > handle_dynamic_tick(action); > > if (!(action->flags & IRQF_DISABLED)) > local_irq_enable_in_hardirq(); > > just removing the if() and the explicit IRQ enabling already makes irqs no longer nest...
I can see why that would raise eyebrows. I can see getting bashed mercilessly with interrupt latency concerns as a result here. Can you suggest any defenses?
-- wli - 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/
| |