From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751435AbaKFVCf (ORCPT ); Thu, 6 Nov 2014 16:02:35 -0500 Received: from mail-wi0-f172.google.com ([209.85.212.172]:47780 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229AbaKFVCb (ORCPT ); Thu, 6 Nov 2014 16:02:31 -0500 Message-ID: <545BE1DE.6060900@linaro.org> Date: Thu, 06 Nov 2014 22:02:22 +0100 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Geert Uytterhoeven , Ingo Molnar , Nicolas Pitre CC: Paul McKenney , Jiri Kosina , "Rafael J. Wysocki" , Linux PM list , Linux-sh list , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: (bisected) Lock up on sh73a0/kzm9g on cpuidle initialization References: In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/06/2014 09:38 PM, Geert Uytterhoeven wrote: > When CONFIG_CPU_IDLE=y, the kernel locks up during cpuidle initialization > on Renesas sh73a0/kzm9g-reference, which has a dual-core Cortex-A9. > > Last message is: > > DMA: preallocated 256 KiB pool for atomic coherent allocations > > After this it's supposed to print: > > cpuidle: using governor ladder > cpuidle: using governor menu > > I've bisected this to commit 442bf3aaf55a91ebfec71da46a4ee10a3c905bcc > ("sched: Let the scheduler see CPU idle states"). > > Reverting that commit, and commit 83a0a96a5f26d974580fd7251043ff70c8f1823d > ("sched/fair: Leverage the idle state info when choosing the "idlest" > cpu") which > depends on it, fixes the problem. > > I saw the discussion "lockdep splat in CPU hotplug", so I enabled lockdep > debugging, but didn't see a lockdep splat. Did you try the fix attached ? https://lkml.org/lkml/2014/10/22/722 > I'm using CONFIG_TREE_RCU=y, as this is SMP without PREEMPT. > > Anyone with a clue? > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog