linux-kernel - Re: [PATCH v3] wifi: p54: Fix memory leak in p54_beacon

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Message-ID: <12dcf657-b8d9-4bd5-9bb1-e760dcbf1b30@gmail.com>
Date: Thu, 22 Jan 2026 12:43:21 +0100
From: Christian Lamparter <chunkeey@...il.com>
To: Zilin Guan <zilin@....edu.cn>
Cc: johannes.berg@...el.com, quic_rdevanat@...cinc.com,
 linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
 jianhao.xu@....edu.cn
Subject: Re: [PATCH v3] wifi: p54: Fix memory leak in p54_beacon_update()

On 1/22/26 9:59 AM, Zilin Guan wrote:
> In p54_beacon_update(), beacon is allocated via ieee80211_beacon_get().
> If p54_beacon_format_ie_tim() fails, the function returns immediately
> without freeing the allocated beacon skb, which would lead to a memory
> leak.
> 
> Since no other references to this memory exist, it must be freed locally
> before returning the error. Fix this by freeing the buffer using
> dev_kfree_skb_any() in the error path.
> 
> Note that this error path is unreachable in practice because mac80211
> guarantees a minimum TIM length of 4 bytes for non-S1G devices. This
> change primarily serves to silence static analysis warnings and keep
> the error handling logic complete.
> 
> Compile tested only. Issue found using a prototype static analysis tool
> and code review.
> 
> Signed-off-by: Zilin Guan <zilin@....edu.cn>
Acked-by: Christian Lamparter <chunkeey@...il.com>

This will be picked up automatically, right?

> ---
> Changes in v3:
> - Add a note in the commit message about the code path being unreachable
>    in practice.
> - Remove the Fixes tag as the issue is theoretical and unreachable.
> 
> Changes in v2:
> - Correct the Fixes tag to point to the commit that introduced this issue.
> 
>   drivers/net/wireless/intersil/p54/main.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intersil/p54/main.c b/drivers/net/wireless/intersil/p54/main.c
> index 2ec3655f1a9c..57a62108cbc3 100644
> --- a/drivers/net/wireless/intersil/p54/main.c
> +++ b/drivers/net/wireless/intersil/p54/main.c
> @@ -143,8 +143,10 @@ static int p54_beacon_update(struct p54_common *priv,
>   	if (!beacon)
>   		return -ENOMEM;
>   	ret = p54_beacon_format_ie_tim(beacon);
> -	if (ret)
> +	if (ret) {
> +		dev_kfree_skb_any(beacon);
>   		return ret;
> +	}
>   
>   	/*
>   	 * During operation, the firmware takes care of beaconing.