Re: [Xenomai] issues with debugging enabled

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-11-13 14:41, Gilles Chanteperdrix wrote:
> On 11/13/2013 02:25 PM, Jan Kiszka wrote:
>> On 2013-11-12 21:34, Gilles Chanteperdrix wrote:
>>>
>>> Hi,
>>>
>>> for a change, I ran the xeno-regression-test with a lot of debugging and
>>> options known to having caused problems in the past and found two
>>> issues:
>>>
>>> on x86 SMP, with full dynticks and debugging enabled (preemptible kernel
>>> debugging, mutex, spinlocks, and sleep inside spinlocks), I get the
>>> series of warnings at the end of the mail.
>>
>> We are currently facing crashes inside __switch_to, FPU related
>> (non-existing save area).
> 
> Probably the issue solved by this patch:
> http://git.xenomai.org/?p=ipipe-gch.git;a=commit;h=9b3320eef67e3f118f96065c8c2584b715710d94

Thought I had everything, but I lost track, and it's missing here. Will
merge and give it a try.

> 
> 
>> Once that is sorted out, we can have a look at
>> that scenario as well. Do you have the .config online somewhere?
> 
> http://sisyphus.hd.free.fr/~gilles/config-nestor

OK, thanks.

> 
>>> on ARM, when a fault occurs, the fault ode is entered with hardware irqs
>>> off (this is a recent change in the mainline kernel, this code used to
>>> be executed with hardware irqs on), so I do:
>>>
>>> ipipe_stall_root();
>>> hard_local_irq_enabled();
>>>
>>> But the context checking does not like that.
>>>
>>> Any idea how to fix these?
>>
>> Only ARM's SMP version of ipipe_stall_root() contains
>> ipipe_stall_root(), UP and at least x86 do not have this. I understand
>> that it makes sense to deny this call over non-root, but as it is about
>> fixing up imbalances in the pipeline state, ipipe_stall_root() is likely
>> not the best choice. What about open-coding the relevant check for the
>> domain? Maybe it also works to push the check to the end of
>> ipipe_stall_root, i.e. after fixing up the pipeline state.
> 
> I have to run again the test and check what really happens, because like
> Philippe said, it may be that I am using ipipe_stall_root() when
> entering this code over non root context, and that would be incorrect.
> I have to report the trap to the pipeline first so as to give a chance
> to Xenomai to relax the thread, then enable irqs over root.
> 

OK.

Jan

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