On Mon, Jan 06, 2025 at 03:47:43PM +0800, Ma Ke wrote:
> Once device_register() failed, we should call put_device() to
> decrement reference count for cleanup. Or it could cause memory leak.
>
> device_register() includes device_add(). As comment of device_add()
> says, 'if device_add() succeeds, you should call device_del() when you
> want to get rid of it. If device_add() has not succeeded, use only
> put_device() to drop the reference count'.
>
> Found by code review.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
> ---
> Changes in v2:
> - modified the patch as suggestions.
> ---
> arch/arm/common/locomo.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/common/locomo.c b/arch/arm/common/locomo.c
> index 309b74783468..9e48cbb2568e 100644
> --- a/arch/arm/common/locomo.c
> +++ b/arch/arm/common/locomo.c
> @@ -253,6 +253,8 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)
>
> ret = device_register(&dev->dev);
> if (ret) {
> + put_device(&dev->dev);
> + return ret;
> out:
> kfree(dev);
> }
This makes the code layout quite horrible.
Instead, I suggest:
dev = kzalloc(sizeof(...)...
- if (!dev) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!dev)
+ return -ENOMEM;
...
ret = device_register(&dev->dev);
- if (ret) {
- out:
- kfree(dev);
- }
+ if (ret)
+ put_device(&dev->dev);
Thanks.
--
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