Re: [PATCH V4 1/3] thermal: core: call put_device() only after device_register() fails

From: Caleb Connolly
Date: Thu Jan 19 2023 - 10:02:56 EST




On 18/01/2023 08:38, Viresh Kumar wrote:
> put_device() shouldn't be called before a prior call to
> device_register(). __thermal_cooling_device_register() doesn't follow
> that properly and needs fixing. Also
> thermal_cooling_device_destroy_sysfs() is getting called unnecessarily
> on few error paths.
>
> Fix all this by placing the calls at the right place.
>
> Based on initial work done by Caleb Connolly.
>
> Fixes: 4748f9687caa ("thermal: core: fix some possible name leaks in error paths")
> Fixes: c408b3d1d9bb ("thermal: Validate new state in cur_state_store()")
> Reported-by: Caleb Connolly <caleb.connolly@xxxxxxxxxx>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

Tested-by: Caleb Connolly <caleb.connolly@xxxxxxxxxx>

Thanks for sending this, with this I no longer hit the splats when
get_max_state() fails.
> ---
> For v6.2-rc.
>
> V3->V4:
> - The first three versions were sent by Caleb.
> - The new version fixes the current bugs, without looking to optimize the
> code any further, which is done separately in the next two patches.
>
> drivers/thermal/thermal_core.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index f17ab2316dbd..77bd47d976a2 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -909,15 +909,20 @@ __thermal_cooling_device_register(struct device_node *np,
> cdev->devdata = devdata;
>
> ret = cdev->ops->get_max_state(cdev, &cdev->max_state);
> - if (ret)
> - goto out_kfree_type;
> + if (ret) {
> + kfree(cdev->type);
> + goto out_ida_remove;
> + }
>
> thermal_cooling_device_setup_sysfs(cdev);
> +
> ret = dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
> if (ret) {
> + kfree(cdev->type);
> thermal_cooling_device_destroy_sysfs(cdev);
> - goto out_kfree_type;
> + goto out_ida_remove;
> }
> +
> ret = device_register(&cdev->device);
> if (ret)
> goto out_kfree_type;
> @@ -943,6 +948,8 @@ __thermal_cooling_device_register(struct device_node *np,
> thermal_cooling_device_destroy_sysfs(cdev);
> kfree(cdev->type);
> put_device(&cdev->device);
> +
> + /* thermal_release() takes care of the rest */
> cdev = NULL;
> out_ida_remove:
> ida_free(&thermal_cdev_ida, id);

--
Kind Regards,
Caleb (they/them)