From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: usb_wwan regression in 3.6 kernel (bisected to bulk-urb allocation) Date: Thu, 3 Apr 2014 09:18:19 +0200 Message-ID: <20140403071819.GE22587@localhost> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= Cc: Johan Hovold , Greg Kroah-Hartman , Dan Carpenter , linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matthias Urlichs , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-serial@vger.kernel.org On Thu, Apr 03, 2014 at 08:49:40AM +0200, Rafa=C5=82 Mi=C5=82ecki wrote= : > I recently wanted to use my ZTE MF636 modem 19d2:0031 and got NULL > pointer dereference in usb_wwan_write few seconds after plugging it. > This is 100% reproducible. >=20 > BUG: unable to handle kernel NULL pointer dereference at 000000000000= 0058 > IP: [] usb_wwan_write+0xa0/0x2b0 [usb_wwan] >=20 > I've bisected between 3.4 and 3.14 kernels and it has appeared to be = a > regression caused by: >=20 > commit 8e493ca1767d4951ed1322abaa74d6edbca29918 > Author: Johan Hovold > Date: Fri Oct 26 18:44:20 2012 +0200 >=20 > USB: usb_wwan: fix bulk-urb allocation >=20 > Make sure we do not allocate urbs if we do not have a bulk endpoi= nt. >=20 > Legacy code used incorrect assumption to test for bulk endpoints. >=20 > Reverting above patch from the 3.14 release fixes the NULL pointer > dereference for me. >=20 > Could you look into this, please? I can test any debug/fix patches yo= u provide. Thanks for the detailed report. Could you also provide the output of lsusb -vd 19d2:0031 Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html