From c4efd7a770c54964bf2d8c98b2f4fd10be13dc54 Mon Sep 17 00:00:00 2001 From: Simon Schippers Date: Tue, 13 Jan 2026 08:51:38 +0100 Subject: [PATCH] usbnet: fix crash due to missing BQL accounting after resume In commit 7ff14c52049e ("usbnet: Add support for Byte Queue Limits (BQL)"), it was missed that usbnet_resume() may enqueue SKBs using __skb_queue_tail() without reporting them to BQL. As a result, the next call to netdev_completed_queue() triggers a BUG_ON() in dql_completed(), since the SKBs queued during resume were never accounted for. This patch fixes the issue by adding a corresponding netdev_sent_queue() call in usbnet_resume() when SKBs are queued after suspend. Because dev->txq.lock is held at this point, no concurrent calls to netdev_sent_queue() from usbnet_start_xmit() can occur. The crash can be reproduced by generating network traffic (e.g. iperf3 -c ... -t 0), suspending the system, and then waking it up (e.g. rtcwake -m mem -s 5). When testing USB2 Android tethering (cdc_ncm), the system crashed within three suspend/resume cycles without this patch. With the patch applied, no crashes were observed after 90 cycles. Testing with an AX88179 USB Ethernet adapter also showed no crashes. Fixes: 7ff14c52049e ("usbnet: Add support for Byte Queue Limits (BQL)") Reported-by: Bard Liao Tested-by: Bard Liao Tested-by: Simon Schippers Signed-off-by: Simon Schippers Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260113075139.6735-1-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski --- drivers/net/usb/usbnet.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 36742e64cff7..35789ff4dd55 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1984,6 +1984,7 @@ int usbnet_resume(struct usb_interface *intf) } else { netif_trans_update(dev->net); __skb_queue_tail(&dev->txq, skb); + netdev_sent_queue(dev->net, skb->len); } } -- 2.47.3