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From: Thierry Reding <thierry.reding@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	jonathanh@nvidia.com, linux-tegra@vger.kernel.org
Subject: Re: [PATCH v4 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device()
Date: Mon, 5 Oct 2020 11:51:32 +0200	[thread overview]
Message-ID: <20201005095132.GH425362@ulmo> (raw)
In-Reply-To: <b1a195cf-0127-0531-f6d1-835367511f57@gmail.com>


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On Fri, Oct 02, 2020 at 05:22:41PM +0300, Dmitry Osipenko wrote:
> 02.10.2020 09:08, Nicolin Chen пишет:
> >  static int tegra_smmu_of_xlate(struct device *dev,
> >  			       struct of_phandle_args *args)
> >  {
> > +	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
> > +	struct tegra_mc *mc = platform_get_drvdata(iommu_pdev);
> >  	u32 id = args->args[0];
> >  
> > +	of_node_put(args->np);
> > +
> > +	if (!mc || !mc->smmu)
> > +		return -EPROBE_DEFER;
> 
> platform_get_drvdata(NULL) will crash.
> 
> > +	dev_iommu_priv_set(dev, mc->smmu);
> 
> I think put_device(mc->dev) is missed here, doesn't it?

Yeah, I think we'd need that here, otherwise we'd be leaking a
reference. Worse, even, mc->dev is the same device that owns the SMMU,
so we're basically incrementing our own reference here and never
releasing it. We also need that put_device(mc->dev) in the error case
above because we already hold the reference there.

Thierry

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WARNING: multiple messages have this Message-ID (diff)
From: Thierry Reding <thierry.reding@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>,
	joro@8bytes.org, vdumpa@nvidia.com, jonathanh@nvidia.com,
	linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device()
Date: Mon, 5 Oct 2020 11:51:32 +0200	[thread overview]
Message-ID: <20201005095132.GH425362@ulmo> (raw)
In-Reply-To: <b1a195cf-0127-0531-f6d1-835367511f57@gmail.com>

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On Fri, Oct 02, 2020 at 05:22:41PM +0300, Dmitry Osipenko wrote:
> 02.10.2020 09:08, Nicolin Chen пишет:
> >  static int tegra_smmu_of_xlate(struct device *dev,
> >  			       struct of_phandle_args *args)
> >  {
> > +	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
> > +	struct tegra_mc *mc = platform_get_drvdata(iommu_pdev);
> >  	u32 id = args->args[0];
> >  
> > +	of_node_put(args->np);
> > +
> > +	if (!mc || !mc->smmu)
> > +		return -EPROBE_DEFER;
> 
> platform_get_drvdata(NULL) will crash.
> 
> > +	dev_iommu_priv_set(dev, mc->smmu);
> 
> I think put_device(mc->dev) is missed here, doesn't it?

Yeah, I think we'd need that here, otherwise we'd be leaking a
reference. Worse, even, mc->dev is the same device that owns the SMMU,
so we're basically incrementing our own reference here and never
releasing it. We also need that put_device(mc->dev) in the error case
above because we already hold the reference there.

Thierry

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  parent reply	other threads:[~2020-10-05  9:51 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02  6:08 [PATCH v4 0/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-10-02  6:08 ` Nicolin Chen
2020-10-02  6:08 ` [PATCH v4 1/3] iommu/tegra-smmu: Use fwspec in tegra_smmu_(de)attach_dev Nicolin Chen
2020-10-02  6:08   ` Nicolin Chen
2020-10-02 14:22   ` Dmitry Osipenko
2020-10-02 14:22     ` Dmitry Osipenko
2020-10-02 14:52     ` Dmitry Osipenko
2020-10-02 14:52       ` Dmitry Osipenko
2020-10-02 19:56       ` Nicolin Chen
2020-10-02 19:56         ` Nicolin Chen
2020-10-02 14:26   ` Dmitry Osipenko
2020-10-02 14:26     ` Dmitry Osipenko
2020-10-02 14:41   ` Dmitry Osipenko
2020-10-02 14:41     ` Dmitry Osipenko
2020-10-02 19:45     ` Nicolin Chen
2020-10-02 19:45       ` Nicolin Chen
2020-10-02 20:12       ` Dmitry Osipenko
2020-10-02 20:12         ` Dmitry Osipenko
2020-10-02 23:53         ` Nicolin Chen
2020-10-02 23:53           ` Nicolin Chen
2020-10-03  4:01           ` Dmitry Osipenko
2020-10-03  4:01             ` Dmitry Osipenko
2020-10-02  6:08 ` [PATCH v4 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device() Nicolin Chen
2020-10-02  6:08   ` Nicolin Chen
2020-10-02 14:22   ` Dmitry Osipenko
2020-10-02 14:22     ` Dmitry Osipenko
2020-10-02 14:58     ` Dmitry Osipenko
2020-10-02 14:58       ` Dmitry Osipenko
2020-10-02 19:53       ` Nicolin Chen
2020-10-02 19:53         ` Nicolin Chen
2020-10-05  9:47         ` Thierry Reding
2020-10-05  9:47           ` Thierry Reding
2020-10-02 14:22   ` Dmitry Osipenko
2020-10-02 14:22     ` Dmitry Osipenko
2020-10-02 14:50     ` Dmitry Osipenko
2020-10-02 14:50       ` Dmitry Osipenko
2020-10-05  9:53       ` Thierry Reding
2020-10-05  9:53         ` Thierry Reding
2020-10-05 10:36         ` Dmitry Osipenko
2020-10-05 10:36           ` Dmitry Osipenko
2020-10-05 11:15           ` Thierry Reding
2020-10-05 11:15             ` Thierry Reding
2020-10-05 13:28             ` Dmitry Osipenko
2020-10-05 13:28               ` Dmitry Osipenko
2020-10-05 14:22               ` Thierry Reding
2020-10-05 14:22                 ` Thierry Reding
2020-10-05  9:51     ` Thierry Reding [this message]
2020-10-05  9:51       ` Thierry Reding
2020-10-02 14:23   ` Dmitry Osipenko
2020-10-02 14:23     ` Dmitry Osipenko
2020-10-02 18:01     ` Nicolin Chen
2020-10-02 18:01       ` Nicolin Chen
2020-10-02 18:20       ` Dmitry Osipenko
2020-10-02 18:20         ` Dmitry Osipenko
2020-10-02 15:02   ` Dmitry Osipenko
2020-10-02 15:02     ` Dmitry Osipenko
2020-10-02 18:58     ` Nicolin Chen
2020-10-02 18:58       ` Nicolin Chen
2020-10-05  9:57       ` Thierry Reding
2020-10-05  9:57         ` Thierry Reding
2020-10-06  1:05         ` Nicolin Chen
2020-10-06  1:05           ` Nicolin Chen
2020-10-08  9:53           ` Thierry Reding
2020-10-08  9:53             ` Thierry Reding
2020-10-08 21:12             ` Nicolin Chen
2020-10-08 21:12               ` Nicolin Chen
2020-10-09 12:25               ` Thierry Reding
2020-10-09 12:25                 ` Thierry Reding
2020-10-09 15:54                 ` Nicolin Chen
2020-10-09 15:54                   ` Nicolin Chen
2020-10-02 15:23   ` Dmitry Osipenko
2020-10-02 15:23     ` Dmitry Osipenko
2020-10-02 16:00     ` Dmitry Osipenko
2020-10-02 16:00       ` Dmitry Osipenko
2020-10-02 16:37       ` Dmitry Osipenko
2020-10-02 16:37         ` Dmitry Osipenko
2020-10-02 16:50         ` Dmitry Osipenko
2020-10-02 16:50           ` Dmitry Osipenko
2020-10-02  6:08 ` [PATCH v4 3/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-10-02  6:08   ` Nicolin Chen
2020-10-02 14:35   ` Dmitry Osipenko
2020-10-02 14:35     ` Dmitry Osipenko
2020-10-02 17:45     ` Nicolin Chen
2020-10-02 17:45       ` Nicolin Chen
2020-10-02 18:04       ` Dmitry Osipenko
2020-10-02 18:04         ` Dmitry Osipenko
2020-10-02 18:04   ` Dmitry Osipenko
2020-10-02 18:04     ` Dmitry Osipenko
2020-10-05 10:04   ` Thierry Reding
2020-10-05 10:04     ` Thierry Reding
2020-10-06  0:54     ` Nicolin Chen
2020-10-06  0:54       ` Nicolin Chen

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