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Date: Mon, 2 Mar 2026 18:29:09 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Felix Fietkau <nbd@nbd.name>, Sean Wang <sean.wang@mediatek.com>, Andrew
 Lunn <andrew+netdev@lunn.ch>, "David S. Miller" <davem@davemloft.net>, Eric
 Dumazet <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Matthias
 Brugger <matthias.bgg@gmail.com>, AngeloGioacchino Del Regno
 <angelogioacchino.delregno@collabora.com>, Alexei Starovoitov
 <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Jesper Dangaard
 Brouer <hawk@kernel.org>, John Fastabend <john.fastabend@gmail.com>,
 Stanislav Fomichev <sdf@fomichev.me>, Paolo Valerio <pvalerio@redhat.com>,
 netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 linux-mediatek@lists.infradead.org, bpf@vger.kernel.org
Subject: Re: [PATCH net] net: ethernet: mtk_eth_soc: Reset prog ptr to NULL
 in case of error in mtk_xdp_setup()
Message-ID: <20260302182909.06de1942@kernel.org>
In-Reply-To: <20260227-mtk-xdp-prog-ptr-fix-v1-1-b73d7588b645@kernel.org>
References: <20260227-mtk-xdp-prog-ptr-fix-v1-1-b73d7588b645@kernel.org>
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On Fri, 27 Feb 2026 16:52:11 +0100 Lorenzo Bianconi wrote:
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -3751,8 +3751,16 @@ static int mtk_xdp_setup(struct net_device *dev, struct bpf_prog *prog,
>  	if (old_prog)
>  		bpf_prog_put(old_prog);
>  
> -	if (netif_running(dev) && need_update)
> -		return mtk_open(dev);
> +	if (netif_running(dev) && need_update) {
> +		int err;
> +
> +		err = mtk_open(dev);
> +		if (err) {
> +			rcu_assign_pointer(eth->prog, NULL);
> +
> +			return err;
> +		}
> +	}
>  
>  	return 0;

Maybe there's something special here, not obvious without context,
but why are we setting eth->prog to NULL rather than old_prog?
At the very least the commit message needs to explain..
-- 
pw-bot: cr