Re: [PATCH 1/2] PCI: dwc: Guard RAS DES debugfs deinit

From: Bjorn Helgaas <helgaas@kernel.org>
To: Shuvam Pandey <shuvampandey1@gmail.com>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Yue Wang" <yue.wang@amlogic.com>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Rob Herring" <robh@kernel.org>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Jerome Brunet" <jbrunet@baylibre.com>,
	"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
	"Fan Ni" <fan.ni@samsung.com>,
	"Shradha Todi" <shradha.t@samsung.com>,
	"Hanjie Lin" <hanjie.lin@amlogic.com>,
	linux-pci@vger.kernel.org, linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] PCI: dwc: Guard RAS DES debugfs deinit
Date: Thu, 11 Jun 2026 17:10:00 -0500	[thread overview]
Message-ID: <20260611221000.GA524832@bhelgaas> (raw)
In-Reply-To: <0f97352506d8d813f70f441de4d63fcd5b7d1c3e.1779123847.git.shuvampandey1@gmail.com>

On Mon, May 18, 2026 at 10:44:17PM +0545, Shuvam Pandey wrote:
> dwc_pcie_rasdes_debugfs_init() returns success when the controller has
> no RAS DES capability, leaving pci->debugfs->rasdes_info unset. The
> common debugfs teardown path still calls
> dwc_pcie_rasdes_debugfs_deinit(), which dereferences rasdes_info
> unconditionally.
> 
> Return early when no RAS DES state was allocated. In that case no RAS DES
> mutex was initialized, so there is nothing to destroy.
> 
> Fixes: 4fbfa17f9a07 ("PCI: dwc: Add debugfs based Silicon Debug support for DWC")
> Signed-off-by: Shuvam Pandey <shuvampandey1@gmail.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-debugfs.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-debugfs.c b/drivers/pci/controller/dwc/pcie-designware-debugfs.c
> index d0884253b..c3671cb2f 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-debugfs.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-debugfs.c
> @@ -557,6 +557,9 @@ static void dwc_pcie_rasdes_debugfs_deinit(struct dw_pcie *pci)
>  {
>  	struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info;
>  
> +	if (!rinfo)
> +		return;

I guess this prevents a NULL pointer dereference, right?

>  	mutex_destroy(&rinfo->reg_event_lock);
>  }
>  
> -- 
> 2.50.1 (Apple Git-155)
> 
> 
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