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From: Mat Martineau <mathew.j.martineau@linux.intel.com>
To: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Subject: Re: [PATCH net-next] net: fix GRO skb truesize update
Date: Wed, 4 Aug 2021 12:29:20 -0700 (PDT)	[thread overview]
Message-ID: <5d4fb1de-7cef-b1fd-7513-27da5793f99@linux.intel.com> (raw)
In-Reply-To: <9134e63fd0d42787e4fbd4bd890d330d6fda9f81.1628097645.git.pabeni@redhat.com>

On Wed, 4 Aug 2021, Paolo Abeni wrote:

> commit 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock
> reference") introduces a serious regression at the GRO layer setting
> the wrong truesize for stolen-head skbs.
>
> Restore the correct truesize: SKB_DATA_ALIGN(...) instead of
> SKB_TRUESIZE(...)
>
> Reported-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
> Fixes: 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock reference")
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>

With this patch I'm no longer seeing the WARN_ON_ONCE() fire in 
skb_try_coalesce(). Thanks Paolo!

Tested-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

> ---
> net/core/skbuff.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 97ed77a86bb0..02a603556408 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -4375,7 +4375,7 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
> 		memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
> 		/* We dont need to clear skbinfo->nr_frags here */
>
> -		new_truesize = SKB_TRUESIZE(sizeof(struct sk_buff));
> +		new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
> 		delta_truesize = skb->truesize - new_truesize;
> 		skb->truesize = new_truesize;
> 		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
> --

--
Mat Martineau
Intel

  reply	other threads:[~2021-08-04 19:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 19:07 Paolo Abeni
2021-08-04 19:29 ` Mat Martineau [this message]
2021-08-05 10:40 ` patchwork-bot+netdevbpf

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