Re: [BUG, Regression, bisected] USB mouse causes bug on 1st insert, ignored on 2nd insert, lsusb stuck at usbdev_open

Alan Stern
2010-09-21T14:30:21Z

On Tue, 21 Sep 2010, Jiri Kosina wrote:

> I have just found out that it's actually CONFIG_USB_DYNAMIC_MINORS which
> makes the difference. When unset, the problem doesn't trigger, and
> usb_find_interface() always returns the proper interface. When
> CONFIG_USB_DYNAMIC_MINORS is being used, the oops happen.
>
> I'll look into that.

Apparently the problem is that intf->minors doesn't get initialized
properly. This patch should fix it. Everybody, please try it out.

Alan Stern

Index: usb-2.6/drivers/usb/core/file.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/file.c
+++ usb-2.6/drivers/usb/core/file.c
@@ -159,9 +159,9 @@ void usb_major_cleanup(void)
int usb_register_dev(struct usb_interface *intf,
struct usb_class_driver *class_driver)
{
- int retval = -EINVAL;
+ int retval;
int minor_base = class_driver->minor_base;
- int minor = 0;
+ int minor;
char name[20];
char *temp;

@@ -173,12 +173,17 @@ int usb_register_dev(struct usb_interfac
*/
minor_base = 0;
#endif
- intf->minor = -1;
-
- dbg ("looking for a minor, starting at %d", minor_base);

if (class_driver->fops == NULL)
- goto exit;
+ return -EINVAL;
+ if (intf->minor >= 0)
+ return -EADDRINUSE;
+
+ retval = init_usb_class();
+ if (retval)
+ return retval;
+
+ dev_dbg(&intf->dev, "looking for a minor, starting at %d", minor_base);

down_write(&minor_rwsem);
for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
@@ -186,20 +191,12 @@ int usb_register_dev(struct usb_interfac
continue;

usb_minors[minor] = class_driver->fops;
-
- retval = 0;
+ intf->minor = minor;
break;
}
up_write(&minor_rwsem);
-
- if (retval)
- goto exit;
-
- retval = init_usb_class();
- if (retval)
- goto exit;
-
- intf->minor = minor;
+ if (intf->minor < 0)
+ return -EXFULL;

/* create a usb class device for this usb interface */
snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
@@ -212,12 +209,12 @@ int usb_register_dev(struct usb_interfac
MKDEV(USB_MAJOR, minor), class_driver,
"%s", temp);
if (IS_ERR(intf->usb_dev)) {
+ retval = PTR_ERR(intf->usb_dev);
down_write(&minor_rwsem);
- usb_minors[intf->minor] = NULL;
+ usb_minors[minor] = NULL;
+ intf->minor = -1;
up_write(&minor_rwsem);
- retval = PTR_ERR(intf->usb_dev);
}
-exit:
return retval;
}
EXPORT_SYMBOL_GPL(usb_register_dev);
Index: usb-2.6/drivers/usb/core/message.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/message.c
+++ usb-2.6/drivers/usb/core/message.c
@@ -1803,6 +1803,7 @@ free_interfaces:
intf->dev.groups = usb_interface_groups;
intf->dev.dma_mask = dev->dev.dma_mask;
INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
+ intf->minor = -1;
device_initialize(&intf->dev);
dev_set_name(&intf->dev, "%d-%s:%d.%d",
dev->bus->busnum, dev->devpath,