From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Praveen Kaligineedi <pkaligineedi@google.com>,
	Ziwei Xiao <ziweixiao@google.com>,
	Jordan Rhee <jordanrhee@google.com>,
	Harshitha Ramamurthy <hramamurthy@google.com>,
	Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 6.18 053/217] gve: fix zero-length skb frag with header-split
Date: Thu, 20 Aug 2026 16:53:41 +0200
Message-ID: <20260820145239.213877664@linuxfoundation.org>
In-Reply-To: <20260820145237.531699751@linuxfoundation.org>
References: <20260820145237.531699751@linuxfoundation.org>
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6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jordan Rhee <jordanrhee@google.com>

commit 6bf14575c65569dcded90ef78afb8a6d57323f04 upstream.

When header split is enabled and a header-only packet is
received such as a pure TCP ACK, GVE will indicate an
RX SKB with a zero-length fragment. If this SKB is then
hairpinned and sent back out, the GVE TX path will emit
a zero-length descriptor. Hardware considers this
an illegal descriptor and stops the queue, causing a
TX timeout and interface reset.

Fix it by not adding the zero-length skb frag.

Cc: stable@vger.kernel.org
Fixes: 5e37d8254e7f ("gve: Add header split data path")
Suggested-by: Praveen Kaligineedi <pkaligineedi@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Jordan Rhee <jordanrhee@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Link: https://patch.msgid.link/20260807224315.234152-2-hramamurthy@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/google/gve/gve_rx_dqo.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
@@ -859,6 +859,11 @@ static int gve_rx_dqo(struct napi_struct
 		rx->rx_hsplit_unsplit_pkt += unsplit;
 		rx->rx_hsplit_bytes += hdr_len;
 		u64_stats_update_end(&rx->statss);
+
+		if (!buf_len) {
+			gve_free_buffer(rx, buf_state);
+			return 0;
+		}
 	} else if (!rx->ctx.skb_head && rx->dqo.page_pool &&
 		   netmem_is_net_iov(buf_state->page_info.netmem)) {
 		/* when header split is disabled, the header went to the packet