FAILED: patch "[PATCH] can: gs_usb: gs_usb_receive_bulk_callback(): fix URB memory" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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 <[email protected]>.

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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 7352e1d5932a0e777e39fa4b619801191f57e603
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026012023-ranged-machinist-edb4@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 7352e1d5932a0e777e39fa4b619801191f57e603 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <[email protected]>
Date: Tue, 23 Dec 2025 21:21:39 +0100
Subject: [PATCH] can: gs_usb: gs_usb_receive_bulk_callback(): fix URB memory
leak

In gs_can_open(), the URBs for USB-in transfers are allocated, added to the parent->rx_submitted anchor and submitted. In the complete callback gs_usb_receive_bulk_callback(), the URB is processed and resubmitted. In gs_can_close() the URBs are freed by calling usb_kill_anchored_urbs(parent->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 gs_can_close().

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

index a0233e550a5a..d093babbc320 100644
@@ -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);
 
 	/* USB failure take down all interfaces */

In gs_can_open(), the URBs for USB-in transfers are allocated, added to the parent->rx_submitted anchor and submitted. In the complete callback gs_usb_receive_bulk_callback(), the URB is processed and resubmitted. In gs_can_close() the URBs are freed by calling usb_kill_anchored_urbs(parent->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 gs_can_close().

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

---
 drivers/net/can/usb/gs_usb.c | 2 ++
 1 file changed, 2 insertions(+)

index ffa2a4d92d01..e36745fd2d3b 100644
@@ -402,6 +402,8 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 			  usbcan
 			  );
 
+	usb_anchor_urb(urb, &parent->rx_submitted);
+
 	rc = usb_submit_urb(urb, GFP_ATOMIC);
 
 	/* USB failure take down all interfaces */

2.51.0