From aeaca27c1db3106967ffbb2b517d98c835f6d500 Mon Sep 17 00:00:00 2001 From: Georgios Karantzas Date: Fri, 11 Sep 2026 03:11:43 +0300 Subject: [PATCH] wifi: ath9k_htc: bound TX aggregation to MAX_TX_BUF_SIZE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __hif_usb_tx() dequeues up to MAX_TX_AGGR_NUM (20) frames into a single tx_buf of MAX_TX_BUF_SIZE (32768) bytes, limiting the batch by record count but never by cumulative byte length. With large frames (MTU 2304), 20 aggregated frames of 2292 bytes each exceed the allocation (20 * 2296 = 45920 bytes), so the memcpy() in the loop writes up to 13152 bytes past tx_buf->buf before usb_submit_urb(). Peek the queue head and stop before copying any record that would cross MAX_TX_BUF_SIZE, then dispatch the current batch. Leftover skbs remain queued and are drained on the next URB completion. The byte bound changes the loop's exit semantics: it can now exit before i == tx_skb_cnt - 1. Stock only finalized tx_buf->len on that last index (len += offset), so an early break would submit a URB holding only the last record's length while every dequeued skb is freed on completion, silently dropping frames. Make tx_buf->len a running total and advance tx_buf->offset per record instead; the stride round_up(nskb->len + 4, 4) is identical to the stock stride when the loop runs to completion. Tested on hardware with an MTU 2304 flood: the loop stops at record 15 (len = 32144, offset = 32144, within 32768), no oversized URB is submitted, and MTU 1500 pings pass 20/20. Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") Signed-off-by: Georgios Karantzas Acked-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260911001143.4507-1-gck.kara@gmail.com Signed-off-by: Jeff Johnson --- drivers/net/wireless/ath/ath9k/hif_usb.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index d3491ff08e6e..7d2f292e20c5 100644 --- a/drivers/net/wireless/ath/ath9k/hif_usb.c +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c @@ -14,6 +14,7 @@ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ +#include #include #include "htc.h" @@ -328,11 +329,14 @@ static int __hif_usb_tx(struct hif_device_usb *hif_dev) tx_skb_cnt = min_t(u16, hif_dev->tx.tx_skb_cnt, MAX_TX_AGGR_NUM); for (i = 0; i < tx_skb_cnt; i++) { + nskb = skb_peek(&hif_dev->tx.tx_skb_queue); + if (!nskb) + break; + + if (tx_buf->offset + nskb->len + 4 > MAX_TX_BUF_SIZE) + break; + nskb = __skb_dequeue(&hif_dev->tx.tx_skb_queue); - - /* Should never be NULL */ - BUG_ON(!nskb); - hif_dev->tx.tx_skb_cnt--; buf = tx_buf->buf; @@ -342,13 +346,8 @@ static int __hif_usb_tx(struct hif_device_usb *hif_dev) *hdr++ = cpu_to_le16(ATH_USB_TX_STREAM_MODE_TAG); buf += 4; memcpy(buf, nskb->data, nskb->len); - tx_buf->len = nskb->len + 4; - - if (i < (tx_skb_cnt - 1)) - tx_buf->offset += (((tx_buf->len - 1) / 4) + 1) * 4; - - if (i == (tx_skb_cnt - 1)) - tx_buf->len += tx_buf->offset; + tx_buf->len = tx_buf->offset + nskb->len + 4; + tx_buf->offset += round_up(nskb->len + 4, 4); __skb_queue_tail(&tx_buf->skb_queue, nskb); TX_STAT_INC(hif_dev, skb_queued);