From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Date: Thu, 06 Nov 2014 21:02:22 +0000 Subject: Re: (bisected) Lock up on sh73a0/kzm9g on cpuidle initialization Message-Id: <545BE1DE.6060900@linaro.org> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable To: linux-arm-kernel@lists.infradead.org On 11/06/2014 09:38 PM, Geert Uytterhoeven wrote: > When CONFIG_CPU_IDLE=3Dy, the kernel locks up during cpuidle initializati= on > 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=3Dy, 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 > --=20 Linaro.org =E2=94=82 Open source software for AR= M SoCs Follow Linaro: Facebook | Twitter | Blog