[PATCH] wifi: rtw88: usb: fix memory leaks on USB write failures

luka.gejak
2026-05-01T16:20:48Z

From: Luka Gejak <luka.gejak@linux.dev>

When rtw_usb_write_port() fails to submit a USB Request Block (URB)
(e.g., due to device disconnect or ENOMEM), the completion callback is
never executed.

Currently, the driver ignores the return value of rtw_usb_write_port()
in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). Because these
functions rely on the completion callback to free the socket buffers
(skbs) and the transaction control block (txcb), a submission failure
results in:
1. A memory leak of the allocated skb in rtw_usb_write_data().
2. A memory leak of the txcb structure and all aggregated skbs in
rtw_usb_tx_agg_skb().

Fix this by checking the return value of rtw_usb_write_port(). If it
fails, explicitly free the skb in rtw_usb_write_data(), and properly
purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().

Fixes: e3037485c68e ("rtw88: new Realtek 802.11ac driver")
Cc: stable@vger.kernel.org
Tested-by: Luka Gejak <luka.gejak@linux.dev>
Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
drivers/net/wireless/realtek/rtw88/usb.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c
index 718940ebba31..d430645a3ef3 100644
--- a/drivers/net/wireless/realtek/rtw88/usb.c
+++ b/drivers/net/wireless/realtek/rtw88/usb.c
@@ -456,7 +456,13 @@ static bool rtw_usb_tx_agg_skb(struct rtw_usb *rtwusb, struct sk_buff_head *list
tx_desc = (struct rtw_tx_desc *)skb_head->data;
qsel = le32_get_bits(tx_desc->w1, RTW_TX_DESC_W1_QSEL);

- rtw_usb_write_port(rtwdev, qsel, skb_head, rtw_usb_write_port_tx_complete, txcb);
+ if (rtw_usb_write_port(rtwdev, qsel, skb_head,
+ rtw_usb_write_port_tx_complete, txcb)) {
+ /* URB submission failed, completion won't run, free the queue */
+ skb_queue_purge(&txcb->tx_ack_queue);
+ kfree(txcb);
+ return false;
+ }

return true;
}
@@ -518,8 +524,10 @@ static int rtw_usb_write_data(struct rtw_dev *rtwdev,

ret = rtw_usb_write_port(rtwdev, qsel, skb,
rtw_usb_write_port_complete, skb);
- if (unlikely(ret))
+ if (unlikely(ret)) {
rtw_err(rtwdev, "failed to do USB write, ret=%d\n", ret);
+ dev_kfree_skb_any(skb);
+ }

return ret;
}
--
2.54.0