From: Lorenzo Bianconi <lorenzo@kernel.org>
To: Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, netdev@vger.kernel.org,
Lorenzo Bianconi <lorenzo@kernel.org>
Subject: [PATCH net] net: airoha: Do not read uninitialized fragment address in airoha_dev_xmit()
Date: Fri, 24 Apr 2026 11:00:28 +0200 [thread overview]
Message-ID: <20260424-airoha-xmit-fix-read-frag-v1-1-fdc0a83c79e8@kernel.org> (raw)
The transmit loop in airoha_dev_xmit() reads fragment address and length
during its final iteration, when the loop index equals
skb_shinfo(skb)->nr_frags, at which point the fragment data is
uninitialized. While these values are never consumed, the read itself is
unsafe and may trigger a page fault. Fix this by avoiding the fragment
read on the last iteration.
Additionally, move the skb pointer from the first to the last used packet
descriptor, so that airoha_qdma_tx_napi_poll() defers freeing the skb
until the final descriptor is processed.
Fixes: 23020f0493270 ("net: airoha: Introduce ethernet support for EN7581 SoC")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
drivers/net/ethernet/airoha/airoha_eth.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 2bb0a3ff9810..d3a841908c82 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1997,8 +1997,8 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
struct netdev_queue *txq;
struct airoha_queue *q;
LIST_HEAD(tx_list);
+ int i = 0, qid;
void *data;
- int i, qid;
u16 index;
u8 fport;
@@ -2057,7 +2057,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
list);
index = e - q->entry;
- for (i = 0; i < nr_frags; i++) {
+ while (true) {
struct airoha_qdma_desc *desc = &q->desc[index];
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
dma_addr_t addr;
@@ -2069,7 +2069,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
goto error_unmap;
list_move_tail(&e->list, &tx_list);
- e->skb = i ? NULL : skb;
+ e->skb = i == nr_frags - 1 ? skb : NULL;
e->dma_addr = addr;
e->dma_len = len;
@@ -2088,6 +2088,9 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
WRITE_ONCE(desc->msg1, cpu_to_le32(msg1));
WRITE_ONCE(desc->msg2, cpu_to_le32(0xffff));
+ if (++i == nr_frags)
+ break;
+
data = skb_frag_address(frag);
len = skb_frag_size(frag);
}
---
base-commit: e728258debd553c95d2e70f9cd97c9fde27c7130
change-id: 20260423-airoha-xmit-fix-read-frag-dc6aa001ca4b
Best regards,
--
Lorenzo Bianconi <lorenzo@kernel.org>
next reply other threads:[~2026-04-24 9:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-24 9:00 Lorenzo Bianconi [this message]
2026-04-25 14:10 ` [PATCH net] net: airoha: Do not read uninitialized fragment address in airoha_dev_xmit() Lorenzo Bianconi
2026-04-28 0:39 ` Jakub Kicinski
2026-04-28 5:06 ` Lorenzo Bianconi
2026-04-28 0:50 ` patchwork-bot+netdevbpf
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