linux-kernel - Re: [PATCH] usb: cdns3: host: Add null check for host

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Message-Id: <DFSIOP130201.PFP7SFMSZYFA@bootlin.com>
Date: Mon, 19 Jan 2026 12:08:40 +0100
From: Théo Lebrun <theo.lebrun@...tlin.com>
To: "Abhash Kumar Jha" <a-kumar2@...com>, <gregkh@...uxfoundation.org>,
 <pawell@...ence.com>, <peter.chen@...nel.org>
Cc: <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
 <linux-usb@...r.kernel.org>, <rogerq@...nel.org>, <u-kumar1@...com>,
 <p-mantena@...com>, <theo.lebrun@...tlin.com>
Subject: Re: [PATCH] usb: cdns3: host: Add null check for host_device before
 accessing its members

Hello Abhash,

On Mon Jan 19, 2026 at 9:22 AM CET, Abhash Kumar Jha wrote:
> In cases when the xhci device is not populated, we see a nullptr
> exception when resuming.
>
> Add a nullptr check for the host_dev before accessing its private data.
>
> Fixes: 3a85c1011540 ("usb: host: cdns3: forward lost power information to xhci")
> Signed-off-by: Abhash Kumar Jha <a-kumar2@...com>
> ---
>  drivers/usb/cdns3/host.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/cdns3/host.c b/drivers/usb/cdns3/host.c
> index f0df114c2b53b..8cc7fc1de6193 100644
> --- a/drivers/usb/cdns3/host.c
> +++ b/drivers/usb/cdns3/host.c
> @@ -141,9 +141,12 @@ static void cdns_host_exit(struct cdns *cdns)
>  static int cdns_host_resume(struct cdns *cdns, bool power_lost)
>  {
>  	struct usb_hcd *hcd = platform_get_drvdata(cdns->host_dev);
> -	struct xhci_plat_priv *priv = hcd_to_xhci_priv(hcd);
> +	struct xhci_plat_priv *priv;
>  
> -	priv->power_lost = power_lost;
> +	if (hcd) {
> +		priv = hcd_to_xhci_priv(hcd);
> +		priv->power_lost = power_lost;
> +	}

I am not seeing a codepath making it possible for drvdata to be NULL.
Can you point it out? What HW, what config, etc.

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com