From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: 4.9-rc1 boot regression, ambiguous bisect result Date: Thu, 20 Oct 2016 08:24:00 +0200 Message-ID: <20161020062400.GA28411@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Dan Williams Cc: Matt Fleming , LKML , linux-efi@vger.kernel.org, Peter Jones , Ard Biesheuvel List-Id: linux-efi@vger.kernel.org * 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? You could also try reverts of the suspicious commits, and then, if the reverted kernel works fine, create a more linear history by cherry-picking them in the right order - and then be able to pinpoint the bad commit with a higher confidence. Thanks, Ingo