Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S642371AbdD1TVz (ORCPT ); Fri, 28 Apr 2017 15:21:55 -0400 Received: from mail-it0-f44.google.com ([209.85.214.44]:35564 "EHLO mail-it0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756031AbdD1TVs (ORCPT ); Fri, 28 Apr 2017 15:21:48 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170427232037.GA98375@beast> <20170428075233.GI3390@nuc-i3427.alporthouse.com> From: Kees Cook Date: Fri, 28 Apr 2017 12:21:46 -0700 X-Google-Sender-Auth: xeaiy5_FJBtjVPMh_iBQuh_MdzI Message-ID: Subject: Re: [PATCH] pstore: Solve lockdep warning by moving inode locks To: "Lofstedt, Marta" Cc: Chris Wilson , "linux-kernel@vger.kernel.org" , Anton Vorontsov , Colin Cross , "Luck, Tony" , Namhyung Kim Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1846 Lines: 47 On Fri, Apr 28, 2017 at 2:00 AM, Lofstedt, Marta wrote: > > >> -----Original Message----- >> From: Chris Wilson [mailto:chris@chris-wilson.co.uk] >> Sent: Friday, April 28, 2017 10:53 AM >> To: Kees Cook >> Cc: linux-kernel@vger.kernel.org; Anton Vorontsov ; >> Colin Cross ; Luck, Tony ; >> Lofstedt, Marta ; Namhyung Kim >> >> Subject: Re: [PATCH] pstore: Solve lockdep warning by moving inode locks >> >> On Thu, Apr 27, 2017 at 04:20:37PM -0700, Kees Cook wrote: >> > Lockdep complains about a possible deadlock between mount and unlink >> > (which is technically impossible), but fixing this improves possible >> > future multiple-backend support, and keeps locking in the right order. >> >> I have merged your for-next/pstore branch (which included this patch, so I >> hope I chose correctly ;) into our CI. That should exercise it on the machines >> that we originally found the lockdep splat. That's the branch, yes, thanks! >> >> Thanks, >> -Chris >> > > Chris, I tested this on drm-tip after you merged for-next/pstore. > EFI_VARS_PSTORE is enabled. > I deliberately cause kernel panic and reboot, but unfortunately that kernel doesn't reboot properly. On display I see a bunch of: > "Cleaning orphaned inode ...", but then kernel boot is stuck. > I run this on a BDW NUCi5, which I have been using successfully with pstore-efi for weeks. > Fortunately I had some other pstore enabled kernels, so if I clean out /sys/fs/pstore/* with one of them I can boot above kernel again. Hrmm... if you isolate this down to a different pstore issue, please let me know. I haven't seen filesystem corruption in my tests yet. :P Thanks for testing! -Kees -- Kees Cook Pixel Security