Re: Bug in in spi-bcm53xx (rcu_sched) exposed by 0461a41 ("spi: Pump transfers inside calling context for spi_sync()")

[Rafał Miłecki <zajec5@xxxxxxxxx>]

On 10 February 2016 at 13:48, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Feb 10, 2016 at 01:21:04PM +0100, Rafał Miłecki wrote:
>
>> Unfortunately the bug in spi-bcm53xx isn't obvious for me. I kept
>> looking at its code for a bit but couldn't find anything.
>
>> Knowing the commit that exposed this bug, does it give you any hint
>> what may be wrong with spi-bcm53xx?
>
> It's most likely just hammering the CPU for a very long time without
> scheduling due to doing a long PIO transfers.  That change just removes
> some needless context switching.

The fact is it happens only after flashing firmware, when flash is
formatted for the first time. After flashing some changes from ramfs
are likely flushed to the falsh. I guess it matches your theory of
long time CPU hammering.

Any idea how to handle this?

-- 
Rafał
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