From: Stanislav Fomichev <sdf.kernel@gmail.com>
To: Jason Xing <kerneljasonxing@gmail.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, bjorn@kernel.org, magnus.karlsson@intel.com,
maciej.fijalkowski@intel.com, jonathan.lemon@gmail.com,
sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net,
hawk@kernel.org, john.fastabend@gmail.com, horms@kernel.org,
andrew+netdev@lunn.ch, bpf@vger.kernel.org,
netdev@vger.kernel.org, Jason Xing <kernelxing@tencent.com>
Subject: Re: [PATCH net 1/4] xsk: avoid skb leak in XDP_TX_METADATA case
Date: Mon, 20 Apr 2026 08:22:07 -0700 [thread overview]
Message-ID: <aeZEjZSsVIdpcbFF@devvm17672.vll0.facebook.com> (raw)
In-Reply-To: <20260418045644.28612-2-kerneljasonxing@gmail.com>
On 04/18, Jason Xing wrote:
> From: Jason Xing <kernelxing@tencent.com>
>
> Fix it by explicitly adding kfree_skb() before returning back to its
> caller.
>
> How to reproduce it in virtio_net:
> 1. the current skb is the first one (which means no frag and xs->skb is
> NULL) and users enable metadata feature.
> 2. xsk_skb_metadata() returns a error code.
> 3. the caller xsk_build_skb() clears skb by using 'skb = NULL;'.
> 4. there is no chance to free this skb anymore.
>
> Closes: https://lore.kernel.org/all/20260415085204.3F87AC19424@smtp.kernel.org/
> Fixes: 30c3055f9c0d ("xsk: wrap generic metadata handling onto separate function")
> Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
next prev parent reply other threads:[~2026-04-20 15:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-18 4:56 [PATCH net 0/4] xsk: fix bugs around xsk skb allocation Jason Xing
2026-04-18 4:56 ` [PATCH net 1/4] xsk: avoid skb leak in XDP_TX_METADATA case Jason Xing
2026-04-20 15:22 ` Stanislav Fomichev [this message]
2026-04-20 15:42 ` Stanislav Fomichev
2026-04-20 16:27 ` Stanislav Fomichev
2026-04-21 0:55 ` Jason Xing
2026-04-18 4:56 ` [PATCH net 2/4] xsk: free the skb when hitting the upper bound MAX_SKB_FRAGS Jason Xing
2026-04-20 15:44 ` Stanislav Fomichev
2026-04-18 4:56 ` [PATCH net 3/4] xsk: handle NULL dereference of the skb without frags issue Jason Xing
2026-04-18 4:56 ` [PATCH net 4/4] xsk: fix use-after-free of xs->skb in xsk_build_skb() free_err path Jason Xing
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