Re: [BUG 4.15-rc7] IRQ matrix management errors

[Keith Busch]

On Tue, Jan 16, 2018 at 12:20:18PM +0100, Thomas Gleixner wrote:
> 8<----------------------
> diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
> index f8b03bb8e725..3cc471beb50b 100644
> --- a/arch/x86/kernel/apic/vector.c
> +++ b/arch/x86/kernel/apic/vector.c
> @@ -542,14 +542,17 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq,
>  
>  		err = assign_irq_vector_policy(irqd, info);
>  		trace_vector_setup(virq + i, false, err);
> -		if (err)
> +		if (err) {
> +			irqd->chip_data = NULL;
> +			free_apic_chip_data(apicd);
>  			goto error;
> +		}
>  	}
>  
>  	return 0;
>  
>  error:
> -	x86_vector_free_irqs(domain, virq, i + 1);
> +	x86_vector_free_irqs(domain, virq, i);
>  	return err;
>  }
>  

The patch does indeed fix all the warnings and allows device binding to
succeed, albeit in a degraded performance mode. Despite that, this is
a good fix, and looks applicable to 4.4-stable, so:

Tested-by: Keith Busch <keith.busch@xxxxxxxxx>

I'm still concerned assign_irq_vector_policy is failing. That has
interrupt allocation abandon MSI-x and fall back to legacy IRQ. 

Your patch does address my main concern, though. Are you comfortable
enough to queue this up for 4.15?

Thanks,
Keith