Re: [PATCH v2 2/6] phy: qcom: qmp-usbc: Fix possible NULL-deref on early runtime suspend

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 1/21/26 3:28 PM, Loic Poulain wrote:
> There is a small window where the runtime suspend callback may run
> after pm_runtime_enable() and before pm_runtime_forbid(). In this
> case, a crash occurs because runtime suspend/resume dereferences
> qmp->phy pointer, which is not yet initialized:
>     `if (!qmp->phy->init_count) {`
> 
> This can also occur if user re-enables runtime-pm via the sysfs
> attribute before qmp phy is initialized.
> 
> Use qmp->usb_init_count instead of qmp->phy->init_count to avoid
> depending on the possibly uninitialized phy pointer.
> 
> Fixes: 19281571a4d5 ("phy: qcom: qmp-usb: split USB-C PHY driver")
> Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp-usbc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-usbc.c b/drivers/phy/qualcomm/phy-qcom-qmp-usbc.c
> index 5e7fcb26744a..edfaa14db967 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-usbc.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-usbc.c
> @@ -690,7 +690,7 @@ static int __maybe_unused qmp_usbc_runtime_suspend(struct device *dev)
>  
>  	dev_vdbg(dev, "Suspending QMP phy, mode:%d\n", qmp->mode);
>  
> -	if (!qmp->phy->init_count) {
> +	if (!qmp->usb_init_count) {

This function changed a month ago, please rebase against next

Although I believe this patch becomes unnecessary with 3 in the picture.
I suppose the case that you mention in the commit message, however
improbable, could be fixed by moving the pm call to after devm_phy_create

Although we'd then rely on devlink to make sure a consumer doesn't snatch
the reference halfway through .probe...

Konrad

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