Messages in this thread | | | Date | Tue, 25 Feb 2014 11:27:52 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart. |
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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.Dill@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.
Thanks,
tglx
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