netdev - Re: [PATCH net-next] net: clear skb->sk in skb_release_head

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Message-ID: <20251112052332.GA7608@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
Date: Tue, 11 Nov 2025 21:23:32 -0800
From: Aditya Garg <gargaditya@...ux.microsoft.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: "David S . Miller" <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Kuniyuki Iwashima <kuniyu@...gle.com>,
	Willem de Bruijn <willemb@...gle.com>, netdev@...r.kernel.org,
	eric.dumazet@...il.com, ssengar@...ux.microsoft.com,
	gargaditya@...rosoft.com
Subject: Re: [PATCH net-next] net: clear skb->sk in skb_release_head_state()

On Tue, Nov 11, 2025 at 03:12:35PM +0000, Eric Dumazet wrote:
> skb_release_head_state() inlines skb_orphan().
> 
> We need to clear skb->sk otherwise we can freeze TCP flows
> on a mostly idle host, because skb_fclone_busy() would
> return true as long as the packet is not yet processed by
> skb_defer_free_flush().
> 
> Fixes: 1fcf572211da ("net: allow skb_release_head_state() to be called multiple times")
> Fixes: e20dfbad8aab ("net: fix napi_consume_skb() with alien skbs")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> ---
>  net/core/skbuff.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 4f4d7ab7057f16bcf88f29827a45a9f4a8f43d5c..f34372666e67cee5329d3ba1d3c86f8622facac3 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -1152,6 +1152,7 @@ void skb_release_head_state(struct sk_buff *skb)
>  
>  #endif
>  		skb->destructor = NULL;
> +		skb->sk = NULL;
>  	}
>  	nf_reset_ct(skb);
>  	skb_ext_reset(skb);
> -- 
> 2.52.0.rc1.455.g30608eb744-goog
>

Tested-by: Aditya Garg <gargaditya@...ux.microsoft.com>