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.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.
So it might make sense to change soft_restart to use the raw_local_irq_* calls.