Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34471 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030824AbcCQSCu (ORCPT ); Thu, 17 Mar 2016 14:02:50 -0400 From: Jes Sorensen To: Xose Vazquez Perez Cc: linux-wireless Subject: Re: rtl8xxxu 4.4.5(from f23): I get a panic adding a new device to the driver References: <56E89DD2.7000000@gmail.com> Date: Thu, 17 Mar 2016 14:02:49 -0400 In-Reply-To: (Jes Sorensen's message of "Wed, 16 Mar 2016 09:58:28 -0400") Message-ID: (sfid-20160317_190308_606645_BE8D98CD) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-wireless-owner@vger.kernel.org List-ID: 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) {