On Tue, Sep 21, 2010 at 06:55:36PM +0200, Jiri Kosina wrote: > On Tue, 21 Sep 2010, Greg KH 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. > > > > Wow, what happened to suddenly cause this? Nothing has changed here in > > a long time. > > > > wierd. > > It doesn't hit you if you are calling usb_register_dev() for all the > instances you have, as the first device will have minor '0', the second > one '1', etc. > > But if you are calling usb_find_interface() for devices that have never > been registered through usb_register_dev(), then you have a problem, as > usb_find_interface() will match those unregistered devices (as minor == 0 > in such cases). > > This is probably quite rare scenario, and hiddev (which might be the only > in-kernel driver doing this?) has moved to usb_find_interface() only > recently. Ah, ok, that makes sense, I never thought of someone calling that function if they had never registered a device :) When did hiddev make this change? We need to know that for the -stable backport of this patch. Alan, care to resend the patch in a format I can apply it? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
