Re: 5.11 new lockdep warning related to led-class code (also may involve ata / piix controller)

[Hans de Goede]

Hi,

On 1/12/21 11:30 PM, Pavel Machek wrote:
> Hi!
> 
>> Booting a 5.11-rc2 kernel with lockdep enabled inside a virtualbox vm (which still
>> emulates good old piix ATA controllers) I get the below lockdep splat early on during boot:
>>
>> This seems to be led-class related but also seems to have a (P)ATA
>> part to it. To the best of my knowledge this is a new problem in
>> 5.11 .
> 
> This is on my for-next branch:
> 
> commit 9a5ad5c5b2d25508996f10ee6b428d5df91d9160 (HEAD -> for-next, origin/for-next)
> 
>     leds: trigger: fix potential deadlock with libata
>     
>     We have the following potential deadlock condition:
>     
>      ========================================================
>      WARNING: possible irq lock inversion dependency detected
>      5.10.0-rc2+ #25 Not tainted
>      --------------------------------------------------------
>      swapper/3/0 just changed the state of lock:
>      ffff8880063bd618 (&host->lock){-...}-{2:2}, at: ata_bmdma_interrupt+0x27/0x200
>      but this lock took another, HARDIRQ-READ-unsafe lock in the past:
>       (&trig->leddev_list_lock){.+.?}-{2:2}
> 
> If I'm not mistaken, that should fix your issue.

I can confirm that this fixes things, thanks.

I assume that this will be part of some future 5.11 fixes pull-req?

Regards,

Hans