Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756338AbcJTThT (ORCPT ); Thu, 20 Oct 2016 15:37:19 -0400 Received: from mail-yw0-f174.google.com ([209.85.161.174]:35096 "EHLO mail-yw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753125AbcJTThS (ORCPT ); Thu, 20 Oct 2016 15:37:18 -0400 MIME-Version: 1.0 In-Reply-To: References: <20161020122931.GD19876@codeblueprint.co.uk> From: Dan Williams Date: Thu, 20 Oct 2016 12:37:16 -0700 Message-ID: Subject: Re: 4.9-rc1 boot regression, ambiguous bisect result To: Matt Fleming Cc: LKML , linux-efi@vger.kernel.org, Peter Jones , Ard Biesheuvel , Ingo Molnar 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: 1697 Lines: 37 On Thu, Oct 20, 2016 at 8:22 AM, Dan Williams wrote: > On Thu, Oct 20, 2016 at 5:29 AM, Matt Fleming wrote: >> On Wed, 19 Oct, at 09:04:29PM, Dan Williams wrote: >>> Hi, >>> >>> I am currently unable to boot a Yoga 900 with latest mainline, but 4.8 boots. >>> >>> The symptom is a reboot before the video console is available. >>> >>> I bisected to commit 816e76129ed5 "efi: Allow drivers to reserve boot >>> services forever". However, that commit is known to be broken. The >>> proposed fix, commit 92dc33501bfb "x86/efi: Round EFI memmap >>> reservations to EFI_PAGE_SIZE", also exhibits the reboot problem. >>> >>> During the bisect some of the stopping points landed on commits that >>> caused the boot process to hang rather than cause a reboot. The >>> commits that resulted in a hang are marked "git bisect skip" in this >>> log: https://gist.github.com/djbw/1b501daa98192a42ae848f03bb59c30e >>> >>> I'll try treating those hangs as bad bisect results and re-run the >>> full bisect tomorrow. In the meantime I wonder if the bisect log >>> implicates a better regression candidate? >> >> Could you mail the dmesg output when booting a known working kernel >> with efi=debug ? > > Here it is: > > https://gist.github.com/djbw/cae05e721b159d5ad7b146d7a93f5fa2 I am able to build a kernel and boot the platform with the following set of reverts: Revert "x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE" Revert "x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data" Revert "efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()" Revert "efi: Allow drivers to reserve boot services forever"