From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: (bisected) Lock up on sh73a0/kzm9g on cpuidle initialization Date: Thu, 06 Nov 2014 22:02:22 +0100 Message-ID: <545BE1DE.6060900@linaro.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-sh-owner@vger.kernel.org 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" List-Id: linux-pm@vger.kernel.org On 11/06/2014 09:38 PM, Geert Uytterhoeven wrote: > When CONFIG_CPU_IDLE=3Dy, the kernel locks up during cpuidle initiali= zation > 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 83a0a96a5f26d974580fd7251043ff70c8f= 1823d > ("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 loc= kdep > 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=3Dy, as this is SMP without PREEMPT. > > Anyone with a clue? > > In personal conversations with technical people, I call myself a hack= er. But > when I'm talking to journalists I just say "programmer" or something = like that. > -- Linus Torvalds > --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog