Re: In many cases softlockup can not be reported after disabling IRQ for long time

[TAO HU <tghk48@motorola.com>]

Hi, Don

Thanks for your feedback!

Unfortunately, the hardlockup depends on NMI which is not available on
ARM (Cortex-A9) per my understanding.
Our system uses OMAP4430. Any more suggestions?

On Tue, Jan 31, 2012 at 11:47 PM, Don Zickus <dzickus@redhat.com> wrote:
> On Tue, Jan 31, 2012 at 03:28:09PM +0800, TAO HU wrote:
>> Resend with a new subject
>>
>> On Wed, Jan 25, 2012 at 4:24 PM, TAO HU <tghk48@motorola.com> wrote:
>> > Hi, All
>> >
>> > While playing kernel 3.0.8 with below test code, it does NOT report
>> > any softlockup with 60%~70% chances.
>> > NOTE: the softlockup timeout is set to 10 seconds (i.e.
>> > watchdog_thresh=5) in my test.
>> > ... ...
>> > preempt_disable();
>> > local_irq_disable();
>> > for (i = 0; i < 20; i++)
>> >       mdelay(1000);
>> > local_irq_enable();
>> > preempt_enable();
>> > ... ...
>> >
>> > However, if I remove local_irq_disable()/local_irq_enable() it will
>> > report softlockup with no problem.
>> > I believe it is due to that after local_irq_enable()
>> > touch_softlockup_watchdog() is called prior softlockup timer.
>
> Hi Hu,
>
> Honestly, you should be getting hardlockup warnings if you are disabling
> interrupts.  Do you see anything in the console output?
>
> Cheers,
> Don



-- 
Best Regards
Hu Tao