[PATCH] mfd: stm32-timers: depopulate child devices on populate failure

[PATCH] mfd: stm32-timers: depopulate child devices on populate failure

[Pengpeng Hou]

stm32_timers_probe() releases the timer DMA resources when
of_platform_populate() fails, but it does not depopulate any child
devices that were created before the failure.

The remove path explicitly depopulates child devices before releasing
DMA resources to avoid races with children using DMA.  Apply the same
ordering on the populate failure path.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
 drivers/mfd/stm32-timers.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
index b3dbc02aaf79..1f0aecae83a5 100644
--- a/drivers/mfd/stm32-timers.c
+++ b/drivers/mfd/stm32-timers.c
@@ -329,8 +329,10 @@ static int stm32_timers_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, ddata);
 
 	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
-	if (ret)
+	if (ret) {
+		of_platform_depopulate(&pdev->dev);
 		stm32_timers_dma_remove(dev, ddata);
+	}
 
 	return ret;
 }
-- 
2.50.1 (Apple Git-155)

Re: [PATCH] mfd: stm32-timers: depopulate child devices on populate failure

[Lee Jones]

On Mon, 15 Jun 2026, Pengpeng Hou wrote:

> stm32_timers_probe() releases the timer DMA resources when
> of_platform_populate() fails, but it does not depopulate any child
> devices that were created before the failure.
> 
> The remove path explicitly depopulates child devices before releasing
> DMA resources to avoid races with children using DMA.  Apply the same
> ordering on the populate failure path.
> 
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
>  drivers/mfd/stm32-timers.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
> index b3dbc02aaf79..1f0aecae83a5 100644
> --- a/drivers/mfd/stm32-timers.c
> +++ b/drivers/mfd/stm32-timers.c
> @@ -329,8 +329,10 @@ static int stm32_timers_probe(struct platform_device *pdev)
>  	platform_set_drvdata(pdev, ddata);
>  
>  	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> -	if (ret)
> +	if (ret) {
> +		of_platform_depopulate(&pdev->dev);

It's strange to see an un-winder inside the error handling of its
original call.  We're used to seeing them called only on success during
a subsequent step.

Wouldn't devm_of_platform_populate() be better here instead?

>  		stm32_timers_dma_remove(dev, ddata);
> +	}
>  
>  	return ret;
>  }
> -- 
> 2.50.1 (Apple Git-155)
> 

-- 
Lee Jones