Re: [PATCH] iommu/riscv: Fix unsigned comparison with negative error code

[Nutty.Liu]

On 12/22/2025 11:15 PM, Alper Ak wrote:
> platform_irq_count() can return -EPROBE_DEFER, but irqs_count is
> unsigned. This causes the negative value to wrap around and bypass
> the error check.
>
> Store the return value in a signed integer first and check for
> errors before assigning to irqs_count.
>
> Reported-by: Dan Carpenter <error27@xxxxxxxxx>
> Closes: https://lore.kernel.org/r/202512141551.kZLTle5r-lkp@xxxxxxxxx/
> Signed-off-by: Alper Ak <alperyasinak1@xxxxxxxxx>
> ---
>   drivers/iommu/riscv/iommu-platform.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
Reviewed-by: Nutty Liu <nutty.liu@xxxxxxxxxxx>

Thanks,
Nutty
> diff --git a/drivers/iommu/riscv/iommu-platform.c b/drivers/iommu/riscv/iommu-platform.c
> index 83a28c83f991..5ec8efedbf12 100644
> --- a/drivers/iommu/riscv/iommu-platform.c
> +++ b/drivers/iommu/riscv/iommu-platform.c
> @@ -68,8 +68,13 @@ static int riscv_iommu_platform_probe(struct platform_device *pdev)
>   	iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAPABILITIES);
>   	iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
>   
> -	iommu->irqs_count = platform_irq_count(pdev);
> -	if (iommu->irqs_count <= 0)
> +	ret = platform_irq_count(pdev);
> +	if (ret < 0)
> +		return ret;
> +
> +	iommu->irqs_count = ret;
> +
> +	if (!iommu->irqs_count)
>   		return dev_err_probe(dev, -ENODEV,
>   				     "no IRQ resources provided\n");
>   	if (iommu->irqs_count > RISCV_IOMMU_INTR_COUNT)