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From:   Aleksander Jan Bajkowski <olek2@wp.pl>
To:     hauke@hauke-m.de, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, olek2@wp.pl,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net v2 1/3] net: lantiq_xrx200: confirm skb is allocated before using
Date:   Mon, 15 Aug 2022 16:57:38 +0200
Message-Id: <20220815145740.12075-2-olek2@wp.pl>
In-Reply-To: <20220815145740.12075-1-olek2@wp.pl>
References: <20220815145740.12075-1-olek2@wp.pl>
MIME-Version: 1.0
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Precedence: bulk

xrx200_hw_receive() assumes build_skb() always works and goes straight
to skb_reserve(). However, build_skb() can fail under memory pressure.

Add a check in case build_skb() failed to allocate and return NULL.

Fixes: e015593573b3 ("net: lantiq_xrx200: convert to build_skb")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
---
 drivers/net/ethernet/lantiq_xrx200.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
index 5edb68a8aab1..6a83a6c19484 100644
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -239,6 +239,13 @@ static int xrx200_hw_receive(struct xrx200_chan *ch)
 	}
 
 	skb = build_skb(buf, priv->rx_skb_size);
+	if (!skb) {
+		skb_free_frag(buf);
+		net_dev->stats.rx_dropped++;
+		netdev_err(net_dev, "failed to build skb\n");
+		return -ENOMEM;
+	}
+
 	skb_reserve(skb, NET_SKB_PAD);
 	skb_put(skb, len);
 
-- 
2.30.2