Return-path: Received: from mail-wm0-f54.google.com ([74.125.82.54]:33148 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750962AbcCQUB3 (ORCPT ); Thu, 17 Mar 2016 16:01:29 -0400 Subject: Re: rtl8xxxu 4.4.5(from f23): I get a panic adding a new device to the driver To: Jes Sorensen , Xose Vazquez Perez References: <56E89DD2.7000000@gmail.com> Cc: linux-wireless , "linux-usb@vger.kernel.org" From: poma Message-ID: <56EB0D15.9040103@gmail.com> (sfid-20160317_210134_835197_18D145C1) Date: Thu, 17 Mar 2016 21:01:25 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: 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"); > + dev_warn(&udev->dev, > + "Adding a device via /sys/bus/usb/drivers/rtl8xxxu/new_id is not supported!\n"); > + ret = -ENODEV; > + goto exit; > + } > + > switch (id->idVendor) { > case USB_VENDOR_ID_REALTEK: > switch(id->idProduct) { > Dynamic adding and removing a new device IDs to a USB device drivers via /sys/bus/usb/drivers/.../[new_id|remove_id] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-usb is not supported only with rtl8xxxu?