Re: [PATCH 12/42] PCI: aardvark: Check for virq mapping when processing INTx IRQ

[Marc Zyngier]

On Thu, 06 May 2021 16:31:23 +0100,
Pali Rohár <pali@xxxxxxxxxx> wrote:
> 
> It is possible that we receive spurious INTx interrupt. So add needed check
> before calling generic_handle_irq() function.
> 
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> Reviewed-by: Marek Behún <kabel@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
>  drivers/pci/controller/pci-aardvark.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index 362faddae935..e7089db11f79 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -1106,7 +1106,10 @@ static void advk_pcie_handle_int(struct advk_pcie *pcie)
>  			    PCIE_ISR1_REG);
>  
>  		virq = irq_find_mapping(pcie->irq_domain, i);
> -		generic_handle_irq(virq);
> +		if (virq)
> +			generic_handle_irq(virq);
> +		else
> +			dev_err(&pcie->pdev->dev, "unexpected INT%c IRQ\n", (char)i+'A');

Please don't scream like this. This is the best way to get into a DoS
situation if you interrupt rate is high enough. At least rate-limit
it.

	M.

-- 
Without deviation from the norm, progress is not possible.