linux-kernel - Re: [PATCH 5/6] phy: core: Add missing of_node_put() in of_phy_provider

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Message-ID: <5e828a43-9365-4ac5-b411-0be7188ab8f2@wanadoo.fr>
Date: Sun, 20 Oct 2024 09:23:32 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Zijun Hu <zijun_hu@...oud.com>, Vinod Koul <vkoul@...nel.org>,
 Kishon Vijay Abraham I <kishon@...nel.org>, Felipe Balbi <balbi@...com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Rob Herring <robh@...nel.org>, Arnd Bergmann <arnd@...db.de>,
 Lee Jones <lee@...nel.org>
Cc: stable@...r.kernel.org, linux-phy@...ts.infradead.org,
 netdev@...r.kernel.org, linux-pci@...r.kernel.org,
 linux-kernel@...r.kernel.org, Zijun Hu <quic_zijuhu@...cinc.com>
Subject: Re: [PATCH 5/6] phy: core: Add missing of_node_put() in
 of_phy_provider_lookup()

Le 20/10/2024 à 07:27, Zijun Hu a écrit :
> From: Zijun Hu <quic_zijuhu@...cinc.com>
> 
> The for_each_child_of_node() macro automatically decrements the child
> refcount at the end of every iteration. On early exits, of_node_put()
> must be used to manually decrement the refcount and avoid memory leaks.
> 
> The macro called by of_phy_provider_lookup() has such early exit, but
> it does not call of_node_put() before early exit.
> 
> Fixed by adding missing of_node_put() in of_phy_provider_lookup().
> 
> Fixes: 2a4c37016ca9 ("phy: core: Fix of_phy_provider_lookup to return PHY provider for sub node")
> Cc: stable@...r.kernel.org
> Signed-off-by: Zijun Hu <quic_zijuhu@...cinc.com>
> 
> ---
> The impact of this change is wide since of_phy_provider_lookup()
> is indirectly called by APIs phy_get(), of_phy_get(), and
> devm_of_phy_get_by_index().
> 
> The following kernel mainline commit has similar fix:
> Commit: b337cc3ce475 ("backlight: lm3509_bl: Fix early returns in for_each_child_of_node()")
> ---
>   drivers/phy/phy-core.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 967878b78797..24bd619a33dd 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -143,10 +143,11 @@ static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
>   	list_for_each_entry(phy_provider, &phy_provider_list, list) {
>   		if (phy_provider->dev->of_node == node)
>   			return phy_provider;
> -
>   		for_each_child_of_node(phy_provider->children, child)
> -			if (child == node)
> +			if (child == node) {
> +				of_node_put(child);
>   				return phy_provider;
> +			}

Hi,

Maybe for_each_child_of_node_scoped() to slightly simplify things at the 
same time?

>   	}
>   
>   	return ERR_PTR(-EPROBE_DEFER);
>