FAILED: patch "[PATCH] can: esd_usb: esd_usb_read_bulk_callback(): fix URB memory" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 5a4391bdc6c8357242f62f22069c865b792406b3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026012716-condense-unblended-43b9@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5a4391bdc6c8357242f62f22069c865b792406b3 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Sat, 10 Jan 2026 12:52:27 +0100
Subject: [PATCH] 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@vger.kernel.org
Link: https://patch.msgid.link/20260116-can_usb-fix-memory-leak-v2-2-4b8cb2915571@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

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));
 	}