[PATCH v3 1/2] usb: gadget: goku_udc: move debug output to debugfs

[PATCH v3 1/2] usb: gadget: goku_udc: move debug output to debugfs

[Cheng Lingfei]

goku_udc exposes diagnostic state through /proc/driver/udc. The single
global proc entry collides when more than one controller is probed and
triggers a proc registration warning.

The data is intended only for debugging and is not a userspace ABI. Move it
under the USB debugfs root and use the PCI device name for a per-device
directory. Create the file only after the UDC has been registered.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/2026082616-glue-atlas-0cfd@gregkh
Assisted-by: Codex:gpt-5.6
Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
---
 drivers/usb/gadget/udc/goku_udc.c | 47 +++++++++++++++++++++++++++------------
 drivers/usb/gadget/udc/goku_udc.h |  5 ++++-
 2 files changed, 37 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
index ac2a984c2f87..5ad8633f522b 100644
--- a/drivers/usb/gadget/udc/goku_udc.c
+++ b/drivers/usb/gadget/udc/goku_udc.c
@@ -20,6 +20,7 @@
 // #define	VERBOSE		/* extra debug messages (success too) */
 // #define	USB_TRACE	/* packet-level success messages */
 
+#include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
@@ -30,9 +31,9 @@
 #include <linux/timer.h>
 #include <linux/list.h>
 #include <linux/interrupt.h>
-#include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/device.h>
+#include <linux/usb.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/prefetch.h>
@@ -1050,9 +1051,7 @@ static inline const char *dmastr(void)
 		return "(dma IN)";
 }
 
-#ifdef CONFIG_USB_GADGET_DEBUG_FILES
-
-static const char proc_node_name [] = "driver/udc";
+#ifdef CONFIG_USB_GADGET_DEBUG_FS
 
 #define FOURBITS "%s%s%s%s"
 #define EIGHTBITS FOURBITS FOURBITS
@@ -1134,7 +1133,7 @@ static const char *udc_ep_status(u32 status)
 	return "?";
 }
 
-static int udc_proc_read(struct seq_file *m, void *v)
+static int goku_debugfs_show(struct seq_file *m, void *v)
 {
 	struct goku_udc			*dev = m->private;
 	struct goku_udc_regs __iomem	*regs = dev->regs;
@@ -1246,7 +1245,33 @@ static int udc_proc_read(struct seq_file *m, void *v)
 	local_irq_restore(flags);
 	return 0;
 }
-#endif	/* CONFIG_USB_GADGET_DEBUG_FILES */
+DEFINE_SHOW_ATTRIBUTE(goku_debugfs);
+
+static void goku_debugfs_create(struct goku_udc *dev)
+{
+	dev->debugfs_root =
+		debugfs_create_dir(dev_name(&dev->pdev->dev), usb_debug_root);
+	debugfs_create_file("goku_udc_state", 0400, dev->debugfs_root, dev,
+			    &goku_debugfs_fops);
+}
+
+static void goku_debugfs_remove(struct goku_udc *dev)
+{
+	debugfs_remove_recursive(dev->debugfs_root);
+	dev->debugfs_root = NULL;
+}
+
+#else
+
+static inline void goku_debugfs_create(struct goku_udc *dev)
+{
+}
+
+static inline void goku_debugfs_remove(struct goku_udc *dev)
+{
+}
+
+#endif	/* CONFIG_USB_GADGET_DEBUG_FS */
 
 /*-------------------------------------------------------------------------*/
 
@@ -1718,9 +1743,7 @@ static void goku_remove(struct pci_dev *pdev)
 
 	BUG_ON(dev->driver);
 
-#ifdef CONFIG_USB_GADGET_DEBUG_FILES
-	remove_proc_entry(proc_node_name, NULL);
-#endif
+	goku_debugfs_remove(dev);
 	if (dev->regs)
 		udc_reset(dev);
 	if (dev->got_irq)
@@ -1813,15 +1836,11 @@ static int goku_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (use_dma)
 		pci_set_master(pdev);
 
-
-#ifdef CONFIG_USB_GADGET_DEBUG_FILES
-	proc_create_single_data(proc_node_name, 0, NULL, udc_proc_read, dev);
-#endif
-
 	retval = usb_add_gadget_udc_release(&pdev->dev, &dev->gadget,
 			gadget_release);
 	if (retval)
 		goto err;
+	goku_debugfs_create(dev);
 
 	return 0;
 
diff --git a/drivers/usb/gadget/udc/goku_udc.h b/drivers/usb/gadget/udc/goku_udc.h
index 70023d401079..4885b1dae928 100644
--- a/drivers/usb/gadget/udc/goku_udc.h
+++ b/drivers/usb/gadget/udc/goku_udc.h
@@ -249,6 +249,10 @@ struct goku_udc {
 					configured:1,
 					enabled:1;
 
+#ifdef CONFIG_USB_GADGET_DEBUG_FS
+	struct dentry			*debugfs_root;
+#endif
+
 	/* pci state used to access those endpoints */
 	struct pci_dev			*pdev;
 	struct goku_udc_regs __iomem	*regs;
@@ -286,4 +290,3 @@ struct goku_udc {
 	xprintk(dev , KERN_WARNING , fmt , ## args)
 #define INFO(dev,fmt,args...) \
 	xprintk(dev , KERN_INFO , fmt , ## args)
-

-- 
2.53.0

Re: [PATCH v3 1/2] usb: gadget: goku_udc: move debug output to debugfs

[Greg Kroah-Hartman]

On Wed, Aug 26, 2026 at 05:15:06PM +0800, Cheng Lingfei wrote:
> goku_udc exposes diagnostic state through /proc/driver/udc. The single
> global proc entry collides when more than one controller is probed and
> triggers a proc registration warning.
> 
> The data is intended only for debugging and is not a userspace ABI. Move it
> under the USB debugfs root and use the PCI device name for a per-device
> directory. Create the file only after the UDC has been registered.
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Link: https://lore.kernel.org/2026082616-glue-atlas-0cfd@gregkh
> Assisted-by: Codex:gpt-5.6
> Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
> ---
>  drivers/usb/gadget/udc/goku_udc.c | 47 +++++++++++++++++++++++++++------------
>  drivers/usb/gadget/udc/goku_udc.h |  5 ++++-
>  2 files changed, 37 insertions(+), 15 deletions(-)

Slow down please.  There's no rush here at all, and by flooding us with
new revisions it doesn't actually allow anyone to review previous ones,
AND it shows you are just pumping out LLM-generated stuff without all
that much thought.

Please wait a few days at the very least before doing new versions of
patch sets.

As pennance, please go and review some outstanding USB patches on the
mailing list, to reduce our review load :)

thanks,

greg k-h

Re: [PATCH v3 1/2] usb: gadget: goku_udc: move debug output to debugfs

[Cheng Lingfei]

On 8/26/2026 5:25 PM, Greg Kroah-Hartman wrote:
> On Wed, Aug 26, 2026 at 05:15:06PM +0800, Cheng Lingfei wrote:
>> goku_udc exposes diagnostic state through /proc/driver/udc. The single
>> global proc entry collides when more than one controller is probed and
>> triggers a proc registration warning.
>>
>> The data is intended only for debugging and is not a userspace ABI. Move it
>> under the USB debugfs root and use the PCI device name for a per-device
>> directory. Create the file only after the UDC has been registered.
>>
>> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Link: https://lore.kernel.org/2026082616-glue-atlas-0cfd@gregkh
>> Assisted-by: Codex:gpt-5.6
>> Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
>> ---
>>   drivers/usb/gadget/udc/goku_udc.c | 47 +++++++++++++++++++++++++++------------
>>   drivers/usb/gadget/udc/goku_udc.h |  5 ++++-
>>   2 files changed, 37 insertions(+), 15 deletions(-)
> 
> Slow down please.  There's no rush here at all, and by flooding us with
> new revisions it doesn't actually allow anyone to review previous ones,
> AND it shows you are just pumping out LLM-generated stuff without all
> that much thought.
> 
> Please wait a few days at the very least before doing new versions of
> patch sets.
> 
> As pennance, please go and review some outstanding USB patches on the
> mailing list, to reduce our review load :)
> 
> thanks,
> 
> greg k-h

Understood, sorry for the noise and the rapid rerolls!

I will slow down, give everyone time to review, and take a look at other
patches on the list as well.

Thanks for the guidance!

-- 
Best regards,
Cheng Lingfei

Re: [PATCH v3 1/2] usb: gadget: goku_udc: move debug output to debugfs

[Greg Kroah-Hartman]

On Wed, Aug 26, 2026 at 05:15:06PM +0800, Cheng Lingfei wrote:
> goku_udc exposes diagnostic state through /proc/driver/udc. The single
> global proc entry collides when more than one controller is probed and
> triggers a proc registration warning.
> 
> The data is intended only for debugging and is not a userspace ABI. Move it
> under the USB debugfs root and use the PCI device name for a per-device
> directory. Create the file only after the UDC has been registered.
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Link: https://lore.kernel.org/2026082616-glue-atlas-0cfd@gregkh
> Assisted-by: Codex:gpt-5.6
> Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
> ---
>  drivers/usb/gadget/udc/goku_udc.c | 47 +++++++++++++++++++++++++++------------
>  drivers/usb/gadget/udc/goku_udc.h |  5 ++++-
>  2 files changed, 37 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
> index ac2a984c2f87..5ad8633f522b 100644
> --- a/drivers/usb/gadget/udc/goku_udc.c
> +++ b/drivers/usb/gadget/udc/goku_udc.c
> @@ -20,6 +20,7 @@
>  // #define	VERBOSE		/* extra debug messages (success too) */
>  // #define	USB_TRACE	/* packet-level success messages */
>  
> +#include <linux/debugfs.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
> @@ -30,9 +31,9 @@
>  #include <linux/timer.h>
>  #include <linux/list.h>
>  #include <linux/interrupt.h>
> -#include <linux/proc_fs.h>
>  #include <linux/seq_file.h>
>  #include <linux/device.h>
> +#include <linux/usb.h>
>  #include <linux/usb/ch9.h>
>  #include <linux/usb/gadget.h>
>  #include <linux/prefetch.h>
> @@ -1050,9 +1051,7 @@ static inline const char *dmastr(void)
>  		return "(dma IN)";
>  }
>  
> -#ifdef CONFIG_USB_GADGET_DEBUG_FILES
> -
> -static const char proc_node_name [] = "driver/udc";
> +#ifdef CONFIG_USB_GADGET_DEBUG_FS

Why do you need this config option check anymore?

[PATCH v3 2/2] usb: gadget: goku_udc: fix kobject warning on probe failure

[Cheng Lingfei]

goku_probe() calls goku_remove() when hardware initialization fails, but
the gadget device is initialized only near the end of probe. As a result,
goku_remove() calls usb_del_gadget_udc(), which drops a reference to an
uninitialized gadget device and triggers a kobject warning.

Initialize the gadget device immediately after allocating the controller,
but add it only after all hardware resources have been acquired. Track the
gadget registration state so goku_remove() can safely clean up both partial
probe state and a fully initialized device.

Use the split gadget removal API and drop the final gadget reference only
after all hardware resources have been released. Obtain the controller from
the embedded gadget device in the release callback because driver data is
set on the PCI device rather than the gadget device.

Fixes: 3301c215a2bb ("USB: UDC: Expand device model API interface")
Reported-by: syzbot+06ec7624018233e17113@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=06ec7624018233e17113
Tested-by: syzbot+06ec7624018233e17113@syzkaller.appspotmail.com
Assisted-by: Codex:gpt-5.6
Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
---
 drivers/usb/gadget/udc/goku_udc.c | 28 ++++++++++++++--------------
 drivers/usb/gadget/udc/goku_udc.h |  3 ++-
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
index 5ad8633f522b..615cc6b8f354 100644
--- a/drivers/usb/gadget/udc/goku_udc.c
+++ b/drivers/usb/gadget/udc/goku_udc.c
@@ -20,6 +20,7 @@
 // #define	VERBOSE		/* extra debug messages (success too) */
 // #define	USB_TRACE	/* packet-level success messages */
 
+#include <linux/container_of.h>
 #include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -1726,7 +1727,7 @@ static irqreturn_t goku_irq(int irq, void *_dev)
 
 static void gadget_release(struct device *_dev)
 {
-	struct goku_udc	*dev = dev_get_drvdata(_dev);
+	struct goku_udc *dev = container_of(_dev, struct goku_udc, gadget.dev);
 
 	kfree(dev);
 }
@@ -1739,7 +1740,8 @@ static void goku_remove(struct pci_dev *pdev)
 
 	DBG(dev, "%s\n", __func__);
 
-	usb_del_gadget_udc(&dev->gadget);
+	if (dev->added)
+		usb_del_gadget(&dev->gadget);
 
 	BUG_ON(dev->driver);
 
@@ -1759,6 +1761,8 @@ static void goku_remove(struct pci_dev *pdev)
 	dev->regs = NULL;
 
 	INFO(dev, "unbind\n");
+
+	usb_put_gadget(&dev->gadget);
 }
 
 /* wrap this driver around the specified pci device, but
@@ -1774,16 +1778,13 @@ static int goku_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	if (!pdev->irq) {
 		printk(KERN_ERR "Check PCI %s IRQ setup!\n", pci_name(pdev));
-		retval = -ENODEV;
-		goto err;
+		return -ENODEV;
 	}
 
 	/* alloc, and start init */
 	dev = kzalloc_obj(*dev);
-	if (!dev) {
-		retval = -ENOMEM;
-		goto err;
-	}
+	if (!dev)
+		return -ENOMEM;
 
 	pci_set_drvdata(pdev, dev);
 	spin_lock_init(&dev->lock);
@@ -1794,6 +1795,8 @@ static int goku_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	/* the "gadget" abstracts/virtualizes the controller */
 	dev->gadget.name = driver_name;
 
+	usb_initialize_gadget(&pdev->dev, &dev->gadget, gadget_release);
+
 	/* now all the pci goodies ... */
 	retval = pci_enable_device(pdev);
 	if (retval < 0) {
@@ -1836,19 +1839,16 @@ static int goku_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (use_dma)
 		pci_set_master(pdev);
 
-	retval = usb_add_gadget_udc_release(&pdev->dev, &dev->gadget,
-			gadget_release);
+	retval = usb_add_gadget(&dev->gadget);
 	if (retval)
 		goto err;
+	dev->added = 1;
 	goku_debugfs_create(dev);
 
 	return 0;
 
 err:
-	if (dev)
-		goku_remove (pdev);
-	/* gadget_release is not registered yet, kfree explicitly */
-	kfree(dev);
+	goku_remove(pdev);
 	return retval;
 }
 
diff --git a/drivers/usb/gadget/udc/goku_udc.h b/drivers/usb/gadget/udc/goku_udc.h
index 4885b1dae928..ed39e7080536 100644
--- a/drivers/usb/gadget/udc/goku_udc.h
+++ b/drivers/usb/gadget/udc/goku_udc.h
@@ -247,7 +247,8 @@ struct goku_udc {
 					got_region:1,
 					req_config:1,
 					configured:1,
-					enabled:1;
+					enabled:1,
+					added:1;
 
 #ifdef CONFIG_USB_GADGET_DEBUG_FS
 	struct dentry			*debugfs_root;

-- 
2.53.0

Re: [PATCH v3 2/2] usb: gadget: goku_udc: fix kobject warning on probe failure

[Greg Kroah-Hartman]

On Wed, Aug 26, 2026 at 05:15:07PM +0800, Cheng Lingfei wrote:
> goku_probe() calls goku_remove() when hardware initialization fails, but
> the gadget device is initialized only near the end of probe. As a result,
> goku_remove() calls usb_del_gadget_udc(), which drops a reference to an
> uninitialized gadget device and triggers a kobject warning.
> 
> Initialize the gadget device immediately after allocating the controller,
> but add it only after all hardware resources have been acquired. Track the
> gadget registration state so goku_remove() can safely clean up both partial
> probe state and a fully initialized device.
> 
> Use the split gadget removal API and drop the final gadget reference only
> after all hardware resources have been released. Obtain the controller from
> the embedded gadget device in the release callback because driver data is
> set on the PCI device rather than the gadget device.
> 
> Fixes: 3301c215a2bb ("USB: UDC: Expand device model API interface")
> Reported-by: syzbot+06ec7624018233e17113@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=06ec7624018233e17113
> Tested-by: syzbot+06ec7624018233e17113@syzkaller.appspotmail.com
> Assisted-by: Codex:gpt-5.6
> Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
> ---
>  drivers/usb/gadget/udc/goku_udc.c | 28 ++++++++++++++--------------
>  drivers/usb/gadget/udc/goku_udc.h |  3 ++-
>  2 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
> index 5ad8633f522b..615cc6b8f354 100644
> --- a/drivers/usb/gadget/udc/goku_udc.c
> +++ b/drivers/usb/gadget/udc/goku_udc.c
> @@ -20,6 +20,7 @@
>  // #define	VERBOSE		/* extra debug messages (success too) */
>  // #define	USB_TRACE	/* packet-level success messages */
>  
> +#include <linux/container_of.h>
>  #include <linux/debugfs.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> @@ -1726,7 +1727,7 @@ static irqreturn_t goku_irq(int irq, void *_dev)
>  
>  static void gadget_release(struct device *_dev)
>  {
> -	struct goku_udc	*dev = dev_get_drvdata(_dev);
> +	struct goku_udc *dev = container_of(_dev, struct goku_udc, gadget.dev);

That looks wrong.  If it is correct, please create a proper macro for it
so that you verify that this all is working properly.