Re: [PATCH] mfd: ab8500: fix child device leaks on probe failure

[Lee Jones <lee@kernel.org>]

On Mon, 21 Sep 2026, Guangshuo Li wrote:

> ab8500_probe() registers MFD child devices before completing the
> remaining device initialization.
> 
> On AB8540, the main MFD device batch may be registered successfully
> before registration of the cut-specific batch fails. In that case,
> the probe returns without removing the child devices registered by
> the earlier mfd_add_devices() call.
> 
> The same issue occurs when sysfs group creation fails after the MFD
> children have been registered. Since the probe returns an error, there
> is no later teardown path to unregister those devices.
> 
> Call mfd_remove_devices() on these error paths so that MFD child
> devices successfully registered earlier in the probe are properly
> unregistered and released.
> 
> The issue was identified by a static analysis tool I developed and
> confirmed by manual review.
> 
> Fixes: cca69b67b3ba ("mfd: Export ab8500 chip id to sysfs")
> Fixes: 9c717cf3fa16 ("mfd: ab8500-core: Add device for new RTC version for AB8540 cut2")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>  drivers/mfd/ab8500-core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mfd/ab8500-core.c b/drivers/mfd/ab8500-core.c
> index f0bc0b5a6f4a..e675223b6023 100644
> --- a/drivers/mfd/ab8500-core.c
> +++ b/drivers/mfd/ab8500-core.c
> @@ -1220,8 +1220,10 @@ static int ab8500_probe(struct platform_device *pdev)
>  		ret = mfd_add_devices(ab8500->dev, 0, ab8500_devs,
>  				ARRAY_SIZE(ab8500_devs), NULL,
>  				0, ab8500->domain);
> -	if (ret)
> +	if (ret) {
> +		mfd_remove_devices(ab8500->dev);

What about switching to devm_*() a.k.a. managed resources?

>  		return ret;
> +	}
>  
>  	/* Add battery management devices */
>  	ret = mfd_add_devices(ab8500->dev, 0, ab8500_bm_devs,
> @@ -1243,8 +1245,10 @@ static int ab8500_probe(struct platform_device *pdev)
>  		ret = sysfs_create_group(&ab8500->dev->kobj,
>  					 &ab8505_attr_group);
>  
> -	if (ret)
> +	if (ret) {
>  		dev_err(ab8500->dev, "error creating sysfs entries\n");
> +		mfd_remove_devices(ab8500->dev);
> +	}
>  
>  	return ret;
>  }
> -- 
> 2.43.0
> 

-- 
Lee Jones