Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751473Ab3HTSS7 (ORCPT ); Tue, 20 Aug 2013 14:18:59 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:41317 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750970Ab3HTSS6 (ORCPT ); Tue, 20 Aug 2013 14:18:58 -0400 Date: Tue, 20 Aug 2013 14:18:57 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Krzysztof Mazur cc: linux-usb@vger.kernel.org, Greg Kroah-Hartman , , Daniel J Blueman Subject: Re: [PATCH 2/2] usb: fail on usb_hub_create_port_device() errors In-Reply-To: <1377019476-7701-3-git-send-email-krzysiek@podlesie.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1258 Lines: 33 On Tue, 20 Aug 2013, Krzysztof Mazur wrote: > Ignoring usb_hub_create_port_device() errors cause later NULL pointer > deference when uninitialized hub->ports[i] entries are dereferenced > after port memory allocation error. > > Signed-off-by: Krzysztof Mazur > --- > I'm not sure if failing in that case is a good idea, but other solutions > are more complex. > > I tried also changing hdev->maxchild and skiping initialization > of later ports, but it didn't work because in some cases > hub->descriptor->bNbrPorts is used instead of hdev->maxchild. > With simulated usb_hub_create_port_device() failure I have an Oops > in hub_power_on(). I think this patch is correct. However, we also should change the other places that refer to bNbrPorts; make them use maxchild instead. > Another possible solution is allowing for uninitialized ports and > checking for hub->ports[i] == NULL. No, if we can't allocate memory for all the ports then the whole thing should fail. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/