From: Jason Xing <kerneljasonxing@gmail•com>
To: 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
Cc: bpf@vger•kernel.org, netdev@vger•kernel.org,
Jason Xing <kernelxing@tencent•com>
Subject: [PATCH net v2 4/5] xsk: drain continuation descs on invalid descriptor in __xsk_generic_xmit()
Date: Fri, 15 May 2026 20:30:17 +0800 [thread overview]
Message-ID: <20260515123018.80147-5-kerneljasonxing@gmail.com> (raw)
In-Reply-To: <20260515123018.80147-1-kerneljasonxing@gmail.com>
From: Jason Xing <kernelxing@tencent•com>
When the TX loop in __xsk_generic_xmit() encounters an invalid
descriptor mid-packet (e.g. an out-of-bounds address), the partial
skb is dropped and the offending descriptor is released. However,
remaining continuation descriptors belonging to the same multi-buffer
packet still sit in the TX ring. Since xs->skb becomes NULL after the
drop, the next iteration treats the leftover continuation fragment as
a brand-new packet, corrupting the packet stream.
Fix this by setting the drain_cont flag when the released descriptor
has XDP_PKT_CONTD set. On the next call to __xsk_generic_xmit(), the
drain logic introduced in the previous patch handles the remaining
fragments with normal CQ backpressure.
Fixes: cf24f5a5feea ("xsk: add support for AF_XDP multi-buffer on Tx path")
Signed-off-by: Jason Xing <kernelxing@tencent•com>
---
net/xdp/xsk.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index f98a9553e536..3b604776f09f 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -1045,6 +1045,8 @@ static int __xsk_generic_xmit(struct sock *sk)
if (xs->skb)
xsk_drop_skb(xs->skb);
xskq_cons_release(xs->tx);
+ if (xp_mb_desc(&desc))
+ xs->drain_cont = true;
}
out:
--
2.41.3
next prev parent reply other threads:[~2026-05-15 12:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-15 12:30 [PATCH net v2 0/5] xsk: fix meta and publish of cq issues Jason Xing
2026-05-15 12:30 ` [PATCH net v2 1/5] xsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata() Jason Xing
2026-05-15 12:30 ` [PATCH net v2 2/5] xsk: fix buffer leak in xsk_drop_skb() for AF_XDP multi-buffer Tx Jason Xing
2026-05-15 12:30 ` [PATCH net v2 3/5] xsk: drain continuation descs after overflow in xsk_build_skb() Jason Xing
2026-05-15 12:30 ` Jason Xing [this message]
2026-05-15 12:30 ` [PATCH net v2 5/5] selftests/xsk: fix multi-buffer invalid desc tests for drain_cont Jason Xing
2026-05-15 16:59 ` [PATCH net v2 0/5] xsk: fix meta and publish of cq issues Maciej Fijalkowski
2026-05-17 2:09 ` Jason Xing
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