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From: Thomas Fourier <fourier.thomas@gmail.com>
Cc: Thomas Fourier <fourier.thomas@gmail.com>,
	Felix Fietkau <nbd@nbd.name>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Sujuan Chen <sujuan.chen@mediatek.com>,
	netdev@vger.kernel.org (open list:MEDIATEK ETHERNET DRIVER),
	linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support),
	linux-arm-kernel@lists.infradead.org (moderated
	list:ARM/Mediatek SoC support),
	linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek
	SoC support)
Subject: [PATCH net-next] net: ethernet: mtk_wed: Fix dma_unmap_single() size
Date: Thu, 15 Oct 2026 16:01:09 +0200	[thread overview]
Message-ID: <20261015140110.41988-2-fourier.thomas@gmail.com> (raw)

In mtk_wed_wo_queue_refill(), the entry->buf is DMA mapped with length
q->buf_size which saved in entry->len. However, in mtk_wed_wo_dequeue(),
the same buffer is DMA unmapped with length buf_len which is set to
SKB_WITH_OVERHEAD(q->buf_size).

Change the size to q->buf_size.

This was discovered with static analysis and was only compile-tested.

Fixes: 799684448e3e ("net: ethernet: mtk_wed: introduce wed wo support")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
---
 drivers/net/ethernet/mediatek/mtk_wed_wo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_wed_wo.c b/drivers/net/ethernet/mediatek/mtk_wed_wo.c
index 7063c78bd35f..4f720ec53e20 100644
--- a/drivers/net/ethernet/mediatek/mtk_wed_wo.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed_wo.c
@@ -99,7 +99,6 @@ static void *
 mtk_wed_wo_dequeue(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q, u32 *len,
 		   bool flush)
 {
-	int buf_len = SKB_WITH_OVERHEAD(q->buf_size);
 	int index = (q->tail + 1) % q->n_desc;
 	struct mtk_wed_wo_queue_entry *entry;
 	struct mtk_wed_wo_queue_desc *desc;
@@ -123,7 +122,7 @@ mtk_wed_wo_dequeue(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q, u32 *len,
 		*len = FIELD_GET(MTK_WED_WO_CTL_SD_LEN0,
 				 le32_to_cpu(READ_ONCE(desc->ctrl)));
 	if (buf)
-		dma_unmap_single(wo->hw->dev, entry->addr, buf_len,
+		dma_unmap_single(wo->hw->dev, entry->addr, q->buf_size,
 				 DMA_FROM_DEVICE);
 	entry->buf = NULL;
 
-- 
2.53.0


             reply	other threads:[~2026-10-15 14:04 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-15 14:01 Thomas Fourier [this message]
2026-10-15 14:19 ` [PATCH net-next] net: ethernet: mtk_wed: Fix dma_unmap_single() size Lorenzo Bianconi

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