Re: threadirqs and kthreadd_task

From: ajay kanala
Date: Thu Oct 23 2014 - 13:18:33 EST


Hi,
any help?

thanks in advance
-- Ajay

On Sat, Oct 18, 2014 at 4:41 PM, ajay kanala <ajaykanala321@xxxxxxxxx> wrote:
> Hi,
> I have been trying to enable "threadirqs" command line option on
> 3.10.12 kernel and kernel crashes with NULL pointer access for
> kthreadd_task in wake_up_process function:
>
> [ 0.000000] Call Trace:
> [ 0.000000] [<8005544c>] wake_up_process+0xc/0x48
> [ 0.000000] [<8004c1b8>] kthread_create_on_node+0x64/0xc4
> [ 0.000000] [<8006d338>] __setup_irq+0x130/0x634
> [ 0.000000] [<8006d89c>] setup_irq+0x60/0xb4
> [ 0.000000] [<8050267c>] icu_of_init+0x1f8/0x2f8
> [ 0.000000] [<80517b30>] of_irq_init+0x2c8/0x304
> [ 0.000000] [<805007bc>] start_kernel+0x218/0x3a4
>
> But as far as i see, kthreadd_task is initialized in start_kernel -->
> rest_init function which is much later than setting up interrupts (
> init_IRQ ):
>
> So my question is, how are systems working which enabled "threadirqs"
> command line option enabled ( the code flow seems similar even on 3.17
> kernel ). Am i missing the obvious?
>
> thanks for pointers
>
> -- Ajay
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