linux-kernel - Re: [PATCH] nvmem: core: add a missing of_node

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Date:   Fri, 23 Apr 2021 10:30:28 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        bgolaszewski@...libre.com, gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] nvmem: core: add a missing of_node_put



On 20/04/2021 21:12, Christophe JAILLET wrote:
> 'for_each_child_of_node' performs an of_node_get on each iteration, so a
> return from the middle of the loop requires an of_node_put.
> 
> Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
>   drivers/nvmem/core.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index bca671ff4e54..4375e52ba6c2 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -686,12 +686,15 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
>   			continue;
>   		if (len < 2 * sizeof(u32)) {
>   			dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
> +			of_node_put(child);
>   			return -EINVAL;
>   		}
>   
>   		cell = kzalloc(sizeof(*cell), GFP_KERNEL);
> -		if (!cell)
> +		if (!cell) {
> +			of_node_put(child);
>   			return -ENOMEM;
> +		}
>   
>   		cell->nvmem = nvmem;
>   		cell->np = of_node_get(child);
> @@ -717,6 +720,7 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
>   			kfree_const(cell->name);
>   			of_node_put(cell->np);
>   			kfree(cell);
> +			of_node_put(child);

two of_node_put looks bit confusing to the reader, can you move the

cell->np = of_node_get(child); just before nvmem_cell_add(cell);
so that we can remove extra put.

Was this reported by some kind of static analysis tool?

--srini



>   			return -EINVAL;
>   		}
>   
>