linux-kernel - [PATCH can v2 2/5] can: esd_usb: esd_usb_read_bulk

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Message-Id: <20260116-can_usb-fix-memory-leak-v2-2-4b8cb2915571@pengutronix.de>
Date: Fri, 16 Jan 2026 20:35:15 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Vincent Mailhol <mailhol@...nel.org>, 
 Wolfgang Grandegger <wg@...ndegger.com>, 
 Sebastian Haas <haas@...-wuensche.com>, 
 "David S. Miller" <davem@...emloft.net>, 
 Frank Jungclaus <frank.jungclaus@....eu>, socketcan@....eu, 
 Yasushi SHOJI <yashi@...cecubics.com>, Daniel Berglund <db@...ser.com>, 
 Olivier Sobrie <olivier@...rie.be>, 
 Remigiusz Kołłątaj <remigiusz.kollataj@...ica.com>, 
 Bernd Krumboeck <b.krumboeck@...il.com>
Cc: kernel@...gutronix.de, linux-can@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Marc Kleine-Budde <mkl@...gutronix.de>, 
 stable@...r.kernel.org
Subject: [PATCH can v2 2/5] can: esd_usb: esd_usb_read_bulk_callback(): fix
 URB memory leak

Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").

In esd_usb_open(), the URBs for USB-in transfers are allocated, added to
the dev->rx_submitted anchor and submitted. In the complete callback
esd_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
esd_usb_close() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).

However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in esd_usb_close().

Fix the memory leak by anchoring the URB in the
esd_usb_read_bulk_callback() to the dev->rx_submitted anchor.

Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device")
Cc: stable@...r.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/usb/esd_usb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 08da507faef4..8cc924c47042 100644
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -541,13 +541,20 @@ static void esd_usb_read_bulk_callback(struct urb *urb)
 			  urb->transfer_buffer, ESD_USB_RX_BUFFER_SIZE,
 			  esd_usb_read_bulk_callback, dev);

+	usb_anchor_urb(urb, &dev->rx_submitted);
+
 	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (!err)
+		return;
+
+	usb_unanchor_urb(urb);
+
 	if (err == -ENODEV) {
 		for (i = 0; i < dev->net_count; i++) {
 			if (dev->nets[i])
 				netif_device_detach(dev->nets[i]->netdev);
 		}
-	} else if (err) {
+	} else {
 		dev_err(dev->udev->dev.parent,
 			"failed resubmitting read bulk urb: %pe\n", ERR_PTR(err));
 	}

-- 
2.51.0