Re: [PATCH] power: supply: qcom_battmgr: fix use-after-free of battmgr on remove

Sebastian Reichel <[email protected]> Fri, 31 Jul 2026 23:43:30 +0200

Newsgroups	org.kernel.vger.linux-pm,org.kernel.vger.linux-arm-msm,org.kernel.vger.linux-kernel,org.kernel.vger.stable
Message-ID	<am0V6zvEDsNd8J2L@venus>

Hi,

On Fri, Jul 31, 2026 at 02:20:06AM +0000, Fan Wu wrote:
> qcom_battmgr_pdr_notify() queues enable_work when the PMIC GLINK service
> comes up. The worker recovers battmgr through container_of() and issues a
> firmware request.
> 
> The driver has no remove callback, so a pending or running enable_work can
> access battmgr after devres frees it. The PMIC GLINK client stays on the
> client list until its devres release action, so a PDR notification can
> also queue the work while remove is running.
> 
> Add a remove callback that disables and drains enable_work before devres
> release. Unlike cancel_work_sync(), disable_work_sync() also blocks a later
> PDR notification from queueing the work. Store battmgr with
> auxiliary_set_drvdata() in probe so remove can retrieve it.
> 
> This issue was found by an in-house static analysis tool.
> 
> Fixes: 29e8142b5623 ("power: supply: Introduce Qualcomm PMIC GLINK power supply")
> Cc: [email protected] # v6.10+
> Assisted-by: Codex:gpt-5.6
> Signed-off-by: Fan Wu <[email protected]>
> ---

Your patch leaves a race condition. A notification might arrive
directly after disable_work_sync resulting in scheduling new work
from the notify function.

Considering the driver is fully converted to device managed
resources, it is better to replace INIT_WORK with
devm_work_autocancel() anyways. Just put it to the right location in
the probe function (directly before devm_pmic_glink_client_alloc())
and things should work correctly.

Greetings,

-- Sebastian

>  drivers/power/supply/qcom_battmgr.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
> index 490137a23d..f8c3efd2c9 100644
> --- a/drivers/power/supply/qcom_battmgr.c
> +++ b/drivers/power/supply/qcom_battmgr.c
> @@ -1638,6 +1638,8 @@ static int qcom_battmgr_probe(struct auxiliary_device *adev,
>  	if (!battmgr)
>  		return -ENOMEM;
>  
> +	auxiliary_set_drvdata(adev, battmgr);
> +
>  	battmgr->dev = dev;
>  
>  	psy_cfg.drv_data = battmgr;
> @@ -1729,9 +1731,17 @@ static const struct auxiliary_device_id qcom_battmgr_id_table[] = {
>  };
>  MODULE_DEVICE_TABLE(auxiliary, qcom_battmgr_id_table);
>  
> +static void qcom_battmgr_remove(struct auxiliary_device *adev)
> +{
> +	struct qcom_battmgr *battmgr = auxiliary_get_drvdata(adev);
> +
> +	disable_work_sync(&battmgr->enable_work);
> +}
> +
>  static struct auxiliary_driver qcom_battmgr_driver = {
>  	.name = "pmic_glink_power_supply",
>  	.probe = qcom_battmgr_probe,
> +	.remove = qcom_battmgr_remove,
>  	.id_table = qcom_battmgr_id_table,
>  };
>  
> -- 
> 2.34.1
>

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