From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753785AbaGPVeS (ORCPT ); Wed, 16 Jul 2014 17:34:18 -0400 Received: from infernal.debian.net ([176.28.9.132]:35094 "EHLO infernal.debian.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752136AbaGPVeM (ORCPT ); Wed, 16 Jul 2014 17:34:12 -0400 Date: Wed, 16 Jul 2014 23:34:08 +0200 From: Andreas Bombe To: Jan Kara Cc: linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [REGRESSION] Boot hang with 939f04bec printk: enable interrupts before calling console_trylock_for_printk() Message-ID: <20140716213408.GA8749@amos.fritz.box> References: <20140628225050.GA3484@amos.fritz.box> <20140714083527.GA30550@quack.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140714083527.GA30550@quack.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 14, 2014 at 10:35:27AM +0200, Jan Kara wrote: > On Sun 29-06-14 00:50:50, Andreas Bombe wrote: > > None of the post 3.15 kernel boot for me. They all hang at the GRUB > > screen telling me it loaded and started the kernel, but the kernel > > itself stops before it prints anything (or even replaces the GRUB > > background graphics). > > > > I bisected it down to 939f04bec1a4ef6ba4370b0f34b01decc844b1b1 "printk: > > enable interrupts before calling console_trylock_for_printk()". > > Reverting that patch on the latest kernel (git 24b414d5a7) allows me to > > boot normally. I fixed the conflict in the revert by leaving in the "if > > (in_sched) return printed_len;". > > > > I have the "early printk via the EFI framebuffer" option enabled, > > disabling it made no difference however. > Thanks for report. I've been on vacation so I'm replying with a delay. I > believe this is one of the issues where this patch just uncovers underlying > problem - I belive lockdep tries to report some locking issue in console > driver code (this patch increased lockdep coverage of console driver code) > however we are holding some locks in printk code which make lockdep > deadlock. Can you try running with the attached patch? EUNABLE You forgot to attach a patch.