Re: [PATCH v2 14/14] iommu/tegra: fix device leak on probe_device()

[Johan Hovold <johan@kernel.org>]

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On Thu, Oct 09, 2025 at 09:56:18AM +0200, Thierry Reding wrote:
> On Tue, Oct 07, 2025 at 11:43:27AM +0200, Johan Hovold wrote:

> > @@ -830,10 +830,9 @@ static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
> >  		return NULL;
> >  
> >  	mc = platform_get_drvdata(pdev);
> > -	if (!mc) {
> > -		put_device(&pdev->dev);
> > +	put_device(&pdev->dev);
> > +	if (!mc)
> >  		return NULL;
> > -	}
> >  
> >  	return mc->smmu;
> 
> pdev->dev is what's backing mc, so if we use put_device() here, then the
> MC could go away at any time, right?

Holding a reference to a device does not prevent its driver data from
going away so there is no point in keeping the reference.

But from what I can tell, you don't need to worry about that anyway
since it's the memory controller driver that registers the iommu (and
the driver can't be unbound).

Johan

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