Re: [PATCH] usb: typec: ucsi: glink: fix use-after-free of ucsi on remove

[Heikki Krogerus]

On Tue, Sep 08, 2026 at 06:02:15AM +0000, Fan Wu wrote:
> The pmic_glink client is released by the devres cleanup, which runs
> after pmic_glink_ucsi_remove() has returned, so its notification
> callbacks can queue work until then. Work that runs after
> ucsi_unregister() has been called touches freed state: it dereferences
> the connector array that ucsi_unregister() freed, or registers and
> unregisters the instance a second time.
> 
> Disable both work items with disable_work_sync() before unregistering,
> and unregister only if the instance is still registered.
> 
> This issue was found by an in-house static analysis tool.
> 
> Fixes: 62b5412b1f4a ("usb: typec: ucsi: add PMIC Glink UCSI driver")

+Neil

> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: Codex:gpt-5.6
> Link: https://lore.kernel.org/r/20260227190430.889-1-nathan.c.rebello@xxxxxxxxx
> Co-developed-by: Song Li <songl@xxxxxxxxxx>
> Signed-off-by: Song Li <songl@xxxxxxxxxx>
> Signed-off-by: Fan Wu <fanwu01@xxxxxxxxxx>

Just a note. ucsi_registered was introduced in commit 11bb2ffb6793
("usb: typec: ucsi: Move unregister out of atomic section").

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/ucsi/ucsi_glink.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
> index 12e07b9fe..1db0c88d8 100644
> --- a/drivers/usb/typec/ucsi/ucsi_glink.c
> +++ b/drivers/usb/typec/ucsi/ucsi_glink.c
> @@ -362,6 +362,10 @@ static void pmic_glink_ucsi_destroy(void *data)
>  {
>  	struct pmic_glink_ucsi *ucsi = data;
>  
> +	/* Drain the work items before ucsi_destroy() frees the ucsi instance */
> +	cancel_work_sync(&ucsi->notify_work);
> +	cancel_work_sync(&ucsi->register_work);
> +
>  	/* Protect to make sure we're not in a middle of a transaction from a glink callback */
>  	mutex_lock(&ucsi->lock);
>  	ucsi_destroy(ucsi->ucsi);
> @@ -467,8 +471,15 @@ static void pmic_glink_ucsi_remove(struct auxiliary_device *adev)
>  {
>  	struct pmic_glink_ucsi *ucsi = dev_get_drvdata(&adev->dev);
>  
> -	/* Unregister first to stop having read & writes */
> -	ucsi_unregister(ucsi->ucsi);
> +	/* Callbacks can queue work until devres releases the client */
> +	disable_work_sync(&ucsi->notify_work);
> +	disable_work_sync(&ucsi->register_work);
> +
> +	/* register_work may have unregistered the instance already */
> +	if (ucsi->ucsi_registered) {
> +		ucsi->ucsi_registered = false;
> +		ucsi_unregister(ucsi->ucsi);
> +	}
>  }
>  
>  static const struct auxiliary_device_id pmic_glink_ucsi_id_table[] = {

-- 
heikki