Re: [net,2/3] can: gs_usb: gs_usb_receive_bulk_callback(): fix URB memory leak
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-01-10 22:38:53
Also in:
linux-can, stable
This is an AI-generated review of your patch. For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html --- can: gs_usb: gs_usb_receive_bulk_callback(): fix URB memory leak This patch fixes a memory leak by re-anchoring the URB in gs_usb_receive_bulk_callback() before resubmission. The USB framework unanchors URBs before calling the completion callback, so the URB needs to be re-anchored to be tracked by usb_kill_anchored_urbs() in gs_can_close(). Link: https://patch.msgid.link/20260105-gs_usb-fix-memory-leak-v2-1-cc6ed6438034@pengutronix.de
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index a0233e550a5a..d093babbc320 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c@@ -751,6 +751,8 @@ static void gs_usb_receive_bulk_callback(struct urb *urb) hf, parent->hf_size_rx, gs_usb_receive_bulk_callback, parent); + usb_anchor_urb(urb, &parent->rx_submitted); + rc = usb_submit_urb(urb, GFP_ATOMIC);
If usb_submit_urb() fails here, the URB remains anchored but is never
submitted. When gs_can_close() later calls usb_kill_anchored_urbs(), it
iterates over anchored URBs and calls usb_kill_urb() on each one. For URBs
that were never successfully submitted, use_count is 0, so usb_kill_urb()
returns without unanchoring them. This causes usb_kill_anchored_urbs() to
loop infinitely on the same URB since the anchor list never becomes empty.
Other CAN USB drivers handle this by calling usb_unanchor_urb() when
submission fails. For example, peak_usb_read_bulk_callback() does:
usb_anchor_urb(urb, &dev->rx_submitted);
err = usb_submit_urb(urb, GFP_ATOMIC);
if (!err)
return;
usb_unanchor_urb(urb);
Should similar error handling be added here to avoid potential hangs when
closing the device after a URB submission failure?
/* USB failure take down all interfaces */
if (rc == -ENODEV) {[ ... ]