Return-path: Received: from iolanthe.rowland.org ([192.131.102.54]:40562 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S935600AbcCQUuK (ORCPT ); Thu, 17 Mar 2016 16:50:10 -0400 Date: Thu, 17 Mar 2016 16:50:09 -0400 (EDT) From: Alan Stern To: poma cc: Jes Sorensen , Xose Vazquez Perez , linux-wireless , "linux-usb@vger.kernel.org" Subject: Re: rtl8xxxu 4.4.5(from f23): I get a panic adding a new device to the driver In-Reply-To: <56EB0D15.9040103@gmail.com> Message-ID: (sfid-20160317_215014_673662_48CABA0D) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 17 Mar 2016, poma wrote: > On 17.03.2016 19:02, Jes Sorensen wrote: > > Jes Sorensen writes: > >> Xose Vazquez Perez writes: > >>> Hi, > >>> > >>> If I do: > >>> # echo "0bda 8176" > /sys/bus/usb/drivers/rtl8xxxu/new_id > >> > >> Hi Xose, > >> > >> Yes please don't do that. The rtl8xxxu driver relies on the .driver_info > >> field in struct use_device_id to carry information for the different > >> types of devices. If you hot add a device like above, the driver will > >> fail because that field now contains a NULL pointer. > >> > >> I should probably add a check for it in the probe function, but it will > >> simply be there to spit out a warning that it doesn't work to hot add a > >> device like this. > >> > >> If you build it with CONFIG_RTL8XXXU_UNTESTED the 0bda:8176 should be > >> included in the device list. > >> > >> Cheers, > >> Jes > > > > Hi Xose, > > > > I added the following patch to my tree to avoid this. > > > > Cheers, > > Jes > > > > commit 9202f4947aac1d60084ee79c9b5294eb42ba59dc > > Author: Jes Sorensen > > Date: Thu Mar 17 13:53:48 2016 -0400 > > > > rtl8xxxu: Fix OOPS if user tries to add device via /sys > > > > This driver relies on driver_info in struct usb_device_id, hence > > adding a device via /sys/bus/usb/drivers/rtl8xxxu/new_id would result > > in a NULL pointer dereference. > > > > Instead print a message and return -ENODEV > > > > Reported-by: Xose Vazquez Perez > > Signed-off-by: Jes Sorensen > > > > diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c > > index 8d893f4..55fc00e 100644 > > --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c > > +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c > > @@ -9671,6 +9671,15 @@ static int rtl8xxxu_probe(struct usb_interface *interface, > > > > udev = usb_get_dev(interface_to_usbdev(interface)); > > > > + if (!id->driver_info) { > > + dev_warn(&udev->dev, > > + "rtl8xxxu relies on driver_info in struct usb_device_id.\n"); You should leave out this line. It won't mean anything to the general user. Alan Stern