On 02/25/2014 02:27 AM, Thomas Gleixner wrote: > On Mon, 24 Feb 2014, Russ Dill wrote: >> On 02/24/2014 03:13 PM, Sebastian Capella wrote: >>> Quoting Russell King - ARM Linux (2014-02-22 02:26:17) >>>> On Tue, Feb 18, 2014 at 05:52:07PM -0800, Sebastian Capella >>>> wrote: >>>>> From: Russ Dill <russ.d...@ti.com> >>>>> >>>>> This adds the ability to run soft_restart with >>>>> local_irq/fiq_disable already called. This is helpful for >>>>> the hibernation code paths. >>>> >>>> I'd rather keep this simple. There's no problem with calling >>>> soft_restart with interrupts already disabled. >>>> local_irq_disable()/local_fiq_disable() there should be >>>> harmless. >>> >>> Hi Russell, >>> >>> I'm observing a data abort loop when I replace this call: >>> >>> In the local_irq_disable, it ends up calling >>> trace_hardirqs_off (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), >>> which calls trace_hardirqs_off_caller which checks >>> lockdep_recursion in the current task, but we've switched to a >>> temporary stack with the call_with_stack, and get_current is >>> returning NULL. This triggers a data abort, which calls >>> trace_hardirqs_off again and so on. >>> >>> Do you have any suggestions here? >>> >>> Thanks, >>> >>> Sebastian >>> >> >> So the alternative is to have a version of the call that calls a >> special no trace version of >> local_irq_disable()/local_fiq_disable(). Which would be >> preferable? Having a noirq version of soft_restart seems much >> simpler to me. > > If you want escape the tracer and in that case you really want it > being on a different stack, use raw_local_irq_* which are not > traced.
So it might make sense to change soft_restart to use the raw_local_irq_* calls. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
