FAILED: patch "[PATCH] can: gs_usb: increase max interface to U8_MAX" failed to apply to 5.15-stable tree

PATCH In review [email protected] 2 participants 5 messages Oct 20, 2025 – Oct 27, 2025

Subsystems (2)

Stable branch CAN network drivers

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lore

[email protected]

author maintainer

2025-10-20 08:12 UTC #0 lore raw

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 2a27f6a8fb5722223d526843040f747e9b0e8060
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025102039-detoxify-trustee-aa22@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 2a27f6a8fb5722223d526843040f747e9b0e8060 Mon Sep 17 00:00:00 2001
From: Celeste Liu <[email protected]>
Date: Tue, 30 Sep 2025 19:34:28 +0800
Subject: [PATCH] can: gs_usb: increase max interface to U8_MAX

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD converter[1]. The original developers may have only 3 interfaces device to test so they write 3 here and wait for future change.

During the HSCanT development, we actually used 4 interfaces, so the limitation of 3 is not enough now. But just increase one is not future-proofed. Since the channel index type in gs_host_frame is u8, just make canch[] become a flexible array with a u8 index, so it naturally constraint by U8_MAX and avoid statically allocate 256 pointer for every gs_usb device.

[1]: https://github.com/cherry-embedded/HSCanT-hardware

Fixes d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")

Reported-by Runcheng Lu <[email protected]>

Cc [email protected]

Reviewed-by Vincent Mailhol <[email protected]>

Signed-off-by Celeste Liu <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Kleine-Budde <[email protected]>

drivers/net/can/usb/gs_usb.c +10 ~~-12~~

index c9482d6e947b..9fb4cbbd6d6d 100644
@@ -289,11 +289,6 @@ struct gs_host_frame {
 #define GS_MAX_RX_URBS 30
 #define GS_NAPI_WEIGHT 32
 
-/* Maximum number of interfaces the driver supports per device.
- * Current hardware only supports 3 interfaces. The future may vary.
- */
-#define GS_MAX_INTF 3
-
 struct gs_tx_context {
 	struct gs_can *dev;
 	unsigned int echo_id;

@@ -324,7 +319,6 @@ struct gs_can {
 
 /* usb interface struct */
 struct gs_usb {
-	struct gs_can *canch[GS_MAX_INTF];
 	struct usb_anchor rx_submitted;
 	struct usb_device *udev;

@@ -336,9 +330,11 @@ struct gs_usb {
 
 	unsigned int hf_size_rx;
 	u8 active_channels;
+	u8 channel_cnt;
 
 	unsigned int pipe_in;
 	unsigned int pipe_out;
+	struct gs_can *canch[] __counted_by(channel_cnt);
 };
 
 /* 'allocate' a tx context.

@@ -599,7 +595,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	}
 
 	/* device reports out of range channel id */
-	if (hf->channel >= GS_MAX_INTF)
+	if (hf->channel >= parent->channel_cnt)
 		goto device_detach;
 
 	dev = parent->canch[hf->channel];

@@ -699,7 +695,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
 device_detach:
-		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+		for (rc = 0; rc < parent->channel_cnt; rc++) {
 			if (parent->canch[rc])
 				netif_device_detach(parent->canch[rc]->netdev);
 		}

@@ -1460,17 +1456,19 @@ static int gs_usb_probe(struct usb_interface *intf,
 	icount = dconf.icount + 1;
 	dev_info(&intf->dev, "Configuring for %u interfaces\n", icount);
 
-	if (icount > GS_MAX_INTF) {
+	if (icount > type_max(parent->channel_cnt)) {
 		dev_err(&intf->dev,
 			"Driver cannot handle more that %u CAN interfaces\n",
-			GS_MAX_INTF);
+			type_max(parent->channel_cnt));
 		return -EINVAL;
 	}
 
-	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	parent = kzalloc(struct_size(parent, canch, icount), GFP_KERNEL);
 	if (!parent)
 		return -ENOMEM;
 
+	parent->channel_cnt = icount;
+
 	init_usb_anchor(&parent->rx_submitted);
 
 	usb_set_intfdata(intf, parent);

@@ -1531,7 +1529,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++)
+	for (i = 0; i < parent->channel_cnt; i++)
 		if (parent->canch[i])
 			gs_destroy_candev(parent->canch[i]);

Celeste Liu

2025-10-20 12:25 UTC #1 lore raw

PATCH 1/1 can: gs_usb: increase max interface to U8_MAX

commit 2a27f6a8fb5722223d526843040f747e9b0e8060 upstream

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD converter[1]. The original developers may have only 3 interfaces device to test so they write 3 here and wait for future change.

[1]: https://github.com/cherry-embedded/HSCanT-hardware

Fixes d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")

Reported-by Runcheng Lu <[email protected]>

Cc [email protected]

Reviewed-by Vincent Mailhol <[email protected]>

Signed-off-by Celeste Liu <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Kleine-Budde <[email protected]>

---
 drivers/net/can/usb/gs_usb.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

drivers/net/can/usb/gs_usb.c +11 ~~-12~~

index 7dc4fb574e45..33800bb75064 100644
@@ -157,10 +157,6 @@ struct gs_host_frame {
 #define GS_MAX_TX_URBS 10
 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
 #define GS_MAX_RX_URBS 30
-/* Maximum number of interfaces the driver supports per device.
- * Current hardware only supports 2 interfaces. The future may vary.
- */
-#define GS_MAX_INTF 2
 
 struct gs_tx_context {
 	struct gs_can *dev;

@@ -191,10 +187,11 @@ struct gs_can {
 
 /* usb interface struct */
 struct gs_usb {
-	struct gs_can *canch[GS_MAX_INTF];
 	struct usb_anchor rx_submitted;
 	struct usb_device *udev;
 	u8 active_channels;
+	u8 channel_cnt;
+	struct gs_can *canch[] __counted_by(channel_cnt);
 };
 
 /* 'allocate' a tx context.

@@ -322,7 +319,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	}
 
 	/* device reports out of range channel id */
-	if (hf->channel >= GS_MAX_INTF)
+	if (hf->channel >= usbcan->channel_cnt)
 		goto device_detach;
 
 	dev = usbcan->canch[hf->channel];

@@ -410,7 +407,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
  device_detach:
-		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+		for (rc = 0; rc < usbcan->channel_cnt; rc++) {
 			if (usbcan->canch[rc])
 				netif_device_detach(usbcan->canch[rc]->netdev);
 		}

@@ -993,20 +990,22 @@ static int gs_usb_probe(struct usb_interface *intf,
 	icount = dconf->icount + 1;
 	dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
 
-	if (icount > GS_MAX_INTF) {
+	if (icount > type_max(typeof(dev->channel_cnt))) {
 		dev_err(&intf->dev,
-			"Driver cannot handle more that %d CAN interfaces\n",
-			GS_MAX_INTF);
+			"Driver cannot handle more that %u CAN interfaces\n",
+			type_max(typeof(dev->channel_cnt)));
 		kfree(dconf);
 		return -EINVAL;
 	}
 
-	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	dev = kzalloc(struct_size(dev, canch, icount), GFP_KERNEL);
 	if (!dev) {
 		kfree(dconf);
 		return -ENOMEM;
 	}
 
+	dev->channel_cnt = icount;
+
 	init_usb_anchor(&dev->rx_submitted);
 
 	usb_set_intfdata(intf, dev);

@@ -1047,7 +1046,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++)
+	for (i = 0; i < dev->channel_cnt; i++)
 		if (dev->canch[i])
 			gs_destroy_candev(dev->canch[i]);

Signature · 1 line

2.51.1.dirty

Greg KH

author maintainer

2025-10-27 11:38 UTC #2 lore raw

Re: [PATCH 5.15.y] can: gs_usb: increase max interface to U8_MAX

Quoted 112 lines · Celeste Liu

commit 2a27f6a8fb5722223d526843040f747e9b0e8060 upstream

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD converter[1]. The original developers may have only 3 interfaces device to test so they write 3 here and wait for future change.

[1]: https://github.com/cherry-embedded/HSCanT-hardware

Fixes d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")

Reported-by Runcheng Lu <[email protected]>

Cc [email protected]

Reviewed-by Vincent Mailhol <[email protected]>

Signed-off-by Celeste Liu <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Kleine-Budde <[email protected]>

---
 drivers/net/can/usb/gs_usb.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

drivers/net/can/usb/gs_usb.c +11 ~~-12~~

index 7dc4fb574e45..33800bb75064 100644
@@ -157,10 +157,6 @@ struct gs_host_frame {
 #define GS_MAX_TX_URBS 10
 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
 #define GS_MAX_RX_URBS 30
-/* Maximum number of interfaces the driver supports per device.
- * Current hardware only supports 2 interfaces. The future may vary.
- */
-#define GS_MAX_INTF 2
 
 struct gs_tx_context {
 	struct gs_can *dev;

@@ -191,10 +187,11 @@ struct gs_can {
 
 /* usb interface struct */
 struct gs_usb {
-	struct gs_can *canch[GS_MAX_INTF];
 	struct usb_anchor rx_submitted;
 	struct usb_device *udev;
 	u8 active_channels;
+	u8 channel_cnt;
+	struct gs_can *canch[] __counted_by(channel_cnt);
 };
 
 /* 'allocate' a tx context.

@@ -322,7 +319,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	}
 
 	/* device reports out of range channel id */
-	if (hf->channel >= GS_MAX_INTF)
+	if (hf->channel >= usbcan->channel_cnt)
 		goto device_detach;
 
 	dev = usbcan->canch[hf->channel];

@@ -410,7 +407,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
  device_detach:
-		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+		for (rc = 0; rc < usbcan->channel_cnt; rc++) {
 			if (usbcan->canch[rc])
 				netif_device_detach(usbcan->canch[rc]->netdev);
 		}

@@ -993,20 +990,22 @@ static int gs_usb_probe(struct usb_interface *intf,
 	icount = dconf->icount + 1;
 	dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
 
-	if (icount > GS_MAX_INTF) {
+	if (icount > type_max(typeof(dev->channel_cnt))) {
 		dev_err(&intf->dev,
-			"Driver cannot handle more that %d CAN interfaces\n",
-			GS_MAX_INTF);
+			"Driver cannot handle more that %u CAN interfaces\n",
+			type_max(typeof(dev->channel_cnt)));
 		kfree(dconf);
 		return -EINVAL;
 	}
 
-	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	dev = kzalloc(struct_size(dev, canch, icount), GFP_KERNEL);
 	if (!dev) {
 		kfree(dconf);
 		return -ENOMEM;
 	}
 
+	dev->channel_cnt = icount;
+
 	init_usb_anchor(&dev->rx_submitted);
 
 	usb_set_intfdata(intf, dev);

@@ -1047,7 +1046,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++)
+	for (i = 0; i < dev->channel_cnt; i++)
 		if (dev->canch[i])
 			gs_destroy_candev(dev->canch[i]);

Signature · 1 line

2.51.1.dirty

Breaks the build :(

Celeste Liu

2025-10-27 12:49 UTC #3 lore raw

Re: [PATCH 5.15.y] can: gs_usb: increase max interface to U8_MAX

Quoted 109 lines · Greg KH

Quoted 108 lines · Celeste Liu

commit 2a27f6a8fb5722223d526843040f747e9b0e8060 upstream

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD converter[1]. The original developers may have only 3 interfaces device to test so they write 3 here and wait for future change.

[1]: https://github.com/cherry-embedded/HSCanT-hardware

Fixes d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")

Reported-by Runcheng Lu <[email protected]>

Cc [email protected]

Reviewed-by Vincent Mailhol <[email protected]>

Signed-off-by Celeste Liu <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Kleine-Budde <[email protected]>

---
 drivers/net/can/usb/gs_usb.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

drivers/net/can/usb/gs_usb.c +11 ~~-12~~

index 7dc4fb574e45..33800bb75064 100644
@@ -157,10 +157,6 @@ struct gs_host_frame {
 #define GS_MAX_TX_URBS 10
 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
 #define GS_MAX_RX_URBS 30
-/* Maximum number of interfaces the driver supports per device.
- * Current hardware only supports 2 interfaces. The future may vary.
- */
-#define GS_MAX_INTF 2
 
 struct gs_tx_context {
 	struct gs_can *dev;

@@ -191,10 +187,11 @@ struct gs_can {
 
 /* usb interface struct */
 struct gs_usb {
-	struct gs_can *canch[GS_MAX_INTF];
 	struct usb_anchor rx_submitted;
 	struct usb_device *udev;
 	u8 active_channels;
+	u8 channel_cnt;
+	struct gs_can *canch[] __counted_by(channel_cnt);
 };
 
 /* 'allocate' a tx context.

@@ -322,7 +319,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	}
 
 	/* device reports out of range channel id */
-	if (hf->channel >= GS_MAX_INTF)
+	if (hf->channel >= usbcan->channel_cnt)
 		goto device_detach;
 
 	dev = usbcan->canch[hf->channel];

@@ -410,7 +407,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
  device_detach:
-		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+		for (rc = 0; rc < usbcan->channel_cnt; rc++) {
 			if (usbcan->canch[rc])
 				netif_device_detach(usbcan->canch[rc]->netdev);
 		}

@@ -993,20 +990,22 @@ static int gs_usb_probe(struct usb_interface *intf,
 	icount = dconf->icount + 1;
 	dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
 
-	if (icount > GS_MAX_INTF) {
+	if (icount > type_max(typeof(dev->channel_cnt))) {
 		dev_err(&intf->dev,
-			"Driver cannot handle more that %d CAN interfaces\n",
-			GS_MAX_INTF);
+			"Driver cannot handle more that %u CAN interfaces\n",
+			type_max(typeof(dev->channel_cnt)));
 		kfree(dconf);
 		return -EINVAL;
 	}
 
-	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	dev = kzalloc(struct_size(dev, canch, icount), GFP_KERNEL);
 	if (!dev) {
 		kfree(dconf);
 		return -ENOMEM;
 	}
 
+	dev->channel_cnt = icount;
+
 	init_usb_anchor(&dev->rx_submitted);
 
 	usb_set_intfdata(intf, dev);

@@ -1047,7 +1046,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++)
+	for (i = 0; i < dev->channel_cnt; i++)
 		if (dev->canch[i])
 			gs_destroy_candev(dev->canch[i]);

Quoted 6 lines

Quoted 4 lines
Signature · 1 line
2.51.1.dirty
Breaks the build :(

Sorry, I have sent fixed version. And REALMODE_CFLAGS on x86 on linux-5.15.y lacks -std flag, so it will build failed on GCC 15 because it use c23 by default and the code try to typedef bool/true/false.

Celeste Liu

2025-10-27 12:47 UTC #4 lore raw

PATCH 1/1 can: gs_usb: increase max interface to U8_MAX

In reply to [email protected]

commit 2a27f6a8fb5722223d526843040f747e9b0e8060 upstream

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD converter[1]. The original developers may have only 3 interfaces device to test so they write 3 here and wait for future change.

[1]: https://github.com/cherry-embedded/HSCanT-hardware

Fixes d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")

Reported-by Runcheng Lu <[email protected]>

Cc [email protected]

Reviewed-by Vincent Mailhol <[email protected]>

Signed-off-by Celeste Liu <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Kleine-Budde <[email protected]>

---
 drivers/net/can/usb/gs_usb.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

drivers/net/can/usb/gs_usb.c +11 ~~-12~~

index 7dc4fb574e45..ffa2a4d92d01 100644
@@ -157,10 +157,6 @@ struct gs_host_frame {
 #define GS_MAX_TX_URBS 10
 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
 #define GS_MAX_RX_URBS 30
-/* Maximum number of interfaces the driver supports per device.
- * Current hardware only supports 2 interfaces. The future may vary.
- */
-#define GS_MAX_INTF 2
 
 struct gs_tx_context {
 	struct gs_can *dev;

@@ -191,10 +187,11 @@ struct gs_can {
 
 /* usb interface struct */
 struct gs_usb {
-	struct gs_can *canch[GS_MAX_INTF];
 	struct usb_anchor rx_submitted;
 	struct usb_device *udev;
 	u8 active_channels;
+	u8 channel_cnt;
+	struct gs_can *canch[];
 };
 
 /* 'allocate' a tx context.

@@ -322,7 +319,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	}
 
 	/* device reports out of range channel id */
-	if (hf->channel >= GS_MAX_INTF)
+	if (hf->channel >= usbcan->channel_cnt)
 		goto device_detach;
 
 	dev = usbcan->canch[hf->channel];

@@ -410,7 +407,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
  device_detach:
-		for (rc = 0; rc < GS_MAX_INTF; rc++) {
+		for (rc = 0; rc < usbcan->channel_cnt; rc++) {
 			if (usbcan->canch[rc])
 				netif_device_detach(usbcan->canch[rc]->netdev);
 		}

@@ -993,20 +990,22 @@ static int gs_usb_probe(struct usb_interface *intf,
 	icount = dconf->icount + 1;
 	dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
 
-	if (icount > GS_MAX_INTF) {
+	if (icount > type_max(typeof(dev->channel_cnt))) {
 		dev_err(&intf->dev,
-			"Driver cannot handle more that %d CAN interfaces\n",
-			GS_MAX_INTF);
+			"Driver cannot handle more that %u CAN interfaces\n",
+			type_max(typeof(dev->channel_cnt)));
 		kfree(dconf);
 		return -EINVAL;
 	}
 
-	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	dev = kzalloc(struct_size(dev, canch, icount), GFP_KERNEL);
 	if (!dev) {
 		kfree(dconf);
 		return -ENOMEM;
 	}
 
+	dev->channel_cnt = icount;
+
 	init_usb_anchor(&dev->rx_submitted);
 
 	usb_set_intfdata(intf, dev);

@@ -1047,7 +1046,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++)
+	for (i = 0; i < dev->channel_cnt; i++)
 		if (dev->canch[i])
 			gs_destroy_candev(dev->canch[i]);

Signature · 1 line

2.51.1