[PATCH] phy: qcom-qusb2: Fix NULL pointer dereference on early suspend

[Dmitry Baryshkov]

On Fri, Dec 05, 2025 at 05:04:37PM +0100, Loic Poulain wrote:
> Reorder runtime PM setup to ensure pm_runtime_forbid() is applied before
> enabling runtime PM. This avoids possible early autosuspend and prevents
> qusb2_phy_runtime_suspend() from being called before driver data is
> initialized, which could otherwise lead to a NULL pointer dereference:
> 
> ```
> Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a1
> [...]
> CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.7+ #116 PREEMPT
> Workqueue: pm pm_runtime_work
> pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : qusb2_phy_runtime_suspend+0x14/0x1e0 [phy_qcom_qusb2]
> lr : pm_generic_runtime_suspend+0x2c/0x44
> [...]
> ```
> 
> Fixes: 891a96f65ac3 ("phy: qcom-qusb2: Add support for runtime PM")
> Signed-off-by: Loic Poulain <loic.poulain at oss.qualcomm.com>
> ---
>  drivers/phy/qualcomm/phy-qcom-qusb2.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> index b5514a32ff8f..97bc3755a390 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qusb2.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> @@ -1093,13 +1093,14 @@ static int qusb2_phy_probe(struct platform_device *pdev)
>  		or->hsdisc_trim.override = true;
>  	}
>  
> -	pm_runtime_set_active(dev);
> -	pm_runtime_enable(dev);
> +
>  	/*
> -	 * Prevent runtime pm from being ON by default. Users can enable
> -	 * it using power/control in sysfs.
> +	 * Enable runtime PM support, but forbid it by default.
> +	 * Users can allow it again via the power/control attribute in sysfs.
>  	 */
> +	pm_runtime_set_active(dev);
>  	pm_runtime_forbid(dev);
> +	pm_runtime_enable(dev);

I'd like to point out that the pm_runtime_enable() here isn't followed
up by the pm_runtime_disable() in the remove path (there is none). Would
you mind sending a followup, changing it to use
devm_pm_runtime_enable()?


For the patch:

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at oss.qualcomm.com>



>  
>  	generic_phy = devm_phy_create(dev, NULL, &qusb2_phy_gen_ops);
>  	if (IS_ERR(generic_phy)) {
> -- 
> 2.34.1
> 
> 
> -- 
> linux-phy mailing list
> linux-phy at lists.infradead.org
> https://lists.infradead.org/mailman/listinfo/linux-phy

-- 
With best wishes
Dmitry