From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:32770 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932216AbcCHKrV (ORCPT ); Tue, 8 Mar 2016 05:47:21 -0500 Date: Tue, 8 Mar 2016 10:49:37 +0000 From: Lorenzo Pieralisi To: Bjorn Helgaas Cc: Krzysztof Ha??asa , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel Subject: Re: [PATCH] Fix NULL ptr dereference in pci_bus_assign_domain_nr() on ARM Message-ID: <20160308104937.GA18919@red-moon> References: <20160307223311.GB26149@localhost> <20160308030106.GA18190@red-moon> <20160308042427.GA20580@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160308042427.GA20580@localhost> Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, Mar 07, 2016 at 10:24:27PM -0600, Bjorn Helgaas wrote: [...] > > > Actually, I did find one problem report: > > > http://forum.doozan.com/read.php?2,17868,22070,quote=1 from last May, > > > but apparently it got lost in a forum and never found its way > > > upstream. > > > > > > I reworked the changelog because this problem will affect *any* arch > > > that enables CONFIG_PCI_DOMAINS_GENERIC and supplies NULL "parent" > > > pointers -- ia64, mips, mn10300, s390, x86, etc., would be affected if > > > they enabled CONFIG_PCI_DOMAINS_GENERIC. > > > > > > I also added a "Fixes:" tag for 7c674700098c, since that's the commit > > > that added the generic code we're fixing. Backports of 7c674700098c > > > should also backport this change. > > > > That's really unfortunate, when I moved code from arm64 to generic I > > did not spot this issue in the original code and carried it over, you > > summarized the reasons in the commit log so without any further ado (and > > with my apologies): > > > > Acked-by: Lorenzo Pieralisi > > No worries, it just goes with the territory. What surprises me is > that it took us so long to notice. v4.0 was released almost a year > ago (April 12, 2015), so I can't figure out how nobody noticed until > now. > > And I don't know what happened with the problem report in the forum. > That's a case where somebody *did* notice, but I guess they just gave > up on v4.0 and went back to v3.18. What a shame :) I don't know if > people just have low expectations of Linux, or they feel like it's too > hard to report bugs, or we don't make it easy enough, or we're not > approachable enough, or what. I notice that many times somebody finds > a workaround, and people seem satisfied with that, and we don't get a > chance to fix the real problem. I agree it is a pity the problem was not reported upstream which would have solved the issue (that I should have spotted anyway while moving the code) a long time ago, unfortunately I think it has to do with how often developers/distros upgrade their kernels on these boards/socs and how they interact with upstream, which is a discussion worth having. Thank you ! Lorenzo