Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752393AbdFNPuD (ORCPT ); Wed, 14 Jun 2017 11:50:03 -0400 Received: from ale.deltatee.com ([207.54.116.67]:54248 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751869AbdFNPuB (ORCPT ); Wed, 14 Jun 2017 11:50:01 -0400 To: Linus Walleij , Greg Kroah-Hartman References: <5933fe2d.V33ODGPU9noDVuyF%fengguang.wu@intel.com> <20170606175552.GA12672@bhelgaas-glaptop.roam.corp.google.com> <20170612200852.GA28578@bhelgaas-glaptop.roam.corp.google.com> <61e11e67-6c1b-ef1e-5fb8-a7c9efb17666@deltatee.com> <20170613041842.GA13308@kroah.com> <20170613043416.GB14217@kroah.com> Cc: Bjorn Helgaas , kernel test robot , Linus Torvalds , LKP , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , linux-pci , "linux-kernel@vger.kernel.org" , Bjorn Helgaas , wfg@linux.intel.com, Alan Cox , Arnd Bergmann , David Airlie , David Herrmann , Daniel Vetter From: Logan Gunthorpe Message-ID: Date: Wed, 14 Jun 2017 09:49:52 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.111 X-SA-Exim-Rcpt-To: daniel.vetter@ffwll.ch, dh.herrmann@gmail.com, airlied@linux.ie, arnd@arndb.de, alan@linux.intel.com, wfg@linux.intel.com, bhelgaas@google.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, lkp@01.org, torvalds@linux-foundation.org, fengguang.wu@intel.com, helgaas@kernel.org, gregkh@linuxfoundation.org, linus.walleij@linaro.org X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [Merge tag 'pci-v4.12-changes' of git] 857f864014: BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8 X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1025 Lines: 25 Hi Linus, On 14/06/17 03:59 AM, Linus Walleij wrote: > I started to take a stab at it at one point and incorporated some feedback > from Torvalds etc, it's here: > https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git/commit/?h=chrdev-warn&id=65e5b1e9eb3f777ab7535b74b490e882eeec79d7 Yes, thanks, I did find your work after a google search. However, seeing it seems to recover only a handful of numbers with some significant complexity required it seemed like a stopgap solution anyway. I posted a proposal in this thread that simply extends the dynamic range into a region above 256 which seems to work well. This means regular configurations won't be affected an any configuration requiring more than 20 dynamic majors will simply end up with high numbers. So unless anyone can think of a reason why this won't work, it's my preferred direction. > Making them all dynamic seemed dangerous because I was afraid > of userspace ABI breakage because of old userlands with > static mknod:s. I agree. Logan