Return-Path: Subject: Re: [patch] hid2hci check usb_init return value From: Marcel Holtmann To: Khem Raj Cc: linux-bluetooth@vger.kernel.org In-Reply-To: <20090106181720.GA12186@gmail.com> References: <20081225231444.GA23751@gmail.com> <1230552751.15666.17.camel@californication> <20081230062656.GA31902@gmail.com> <1231210468.13304.20.camel@californication> <20090106181720.GA12186@gmail.com> Content-Type: text/plain Date: Tue, 06 Jan 2009 19:21:04 +0100 Message-Id: <1231266064.14901.0.camel@californication> Mime-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Khem, > > > > > Working on a system which did not have a USB in it. I was getting a > > > > > segfault with hid2hci. The problem tracked down was usb_init () was > > > > > failing and we did not check for it and carried on with execution. > > > > > As a result the next call to libusb failed because we passed in NULL for > > > > > ctx because during usb_init () this should have been malloc'ed if all > > > > > have gone correctly but in case of error usb_init () free's up the > > > > > allocated memory and hence the segfault. > > > > > > > > > > We should check for return value of usb_init () call and exit > > > > > immediately if it fails. Tested on 4.24 release. > > > > > > > > the problem is that usb_init() doesn't return any errors on the versions > > > > that I have here: > > > > > > > > ii libusb-0.1-4 2:0.1.12-12 userspace USB programming library > > > > ii libusb-dev 2:0.1.12-12 userspace USB programming library > > > > > > > > Applying your patch would break complication on multiple platforms. > > > What you have is libusb-0.1 which has older API I suppose. There is > > > libusb-compat which can be used as a wrapper over libusb1 to give > > > libusb0 like interfaces. > > > > > > Actually I was using libusb-1.0.0 API as mentioned here > > > http://libusb.sourceforge.net/api-1.0/group__lib.html > > > that also means that the patch I attached should have been using > > > libusb_init() instead. > > > > > > Here is updated patch > > > > this still breaks with a system that has libusb-0.1 installed like the > > current Ubuntu 8.10 does. So either we switch to libusb-1.0 completely > > or we leave it as it is. > > Moving forward depending on libusb-1.0 seems a better idea to me. feel free to submit patches for all utilities with USB support. Then we can talk about switching. Regards Marcel