From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753441Ab3ERTlE (ORCPT ); Sat, 18 May 2013 15:41:04 -0400 Received: from mout.gmx.net ([212.227.15.15]:53603 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752982Ab3ERTlB (ORCPT ); Sat, 18 May 2013 15:41:01 -0400 X-Authenticated: #1045983 X-Provags-ID: V01U2FsdGVkX18QzUdqm5oQ9RDZrleGcPCyL99kHXKfqNUSEqPUlN Cv9zp4CF1Douei Message-ID: <5197D947.4070200@gmx.de> Date: Sat, 18 May 2013 21:40:55 +0200 From: Helge Deller User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: "Srivatsa S. Bhat" CC: James Bottomley , Thomas Gleixner , linux-parisc@vger.kernel.org, John David Anglin , linux-kernel Subject: Re: [PATCH] parisc: avoid WARNING: at kernel/cpu/idle.c:96 References: <20130508204242.GA16254@p100.box> <1368047134.8623.5.camel@dabdike> <5196843B.8060807@linux.vnet.ibm.com> In-Reply-To: <5196843B.8060807@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/17/2013 09:25 PM, Srivatsa S. Bhat wrote: > On 05/09/2013 02:35 AM, James Bottomley wrote: >> On Wed, 2013-05-08 at 22:42 +0200, Helge Deller wrote: >>> We need to enable local irqs to avoid this runtime warning. >>> >>> Signed-off-by: Helge Deller >>> >>> diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c >>> index 55f92b6..2840d43 100644 >>> --- a/arch/parisc/kernel/process.c >>> +++ b/arch/parisc/kernel/process.c >>> @@ -286,3 +286,8 @@ void *dereference_function_descriptor(void *ptr) >>> return ptr; >>> } >>> #endif >>> + >>> +void arch_cpu_idle(void) >>> +{ >>> + local_irq_enable(); >> >> This is definitely wrong. we'd need at least a cpu_relax() in there. >> Without that the cpu will bounce around in the idle loop. I'd advise >> that we simply keep the default cpu_idle_poll(). >> >> However, this looks like a kernel bug to me in cpu_idle_loop()? not >> something we should be working around in the arch code. >> >> Thomas, what's going on here? It looks like you can never avoid the >> WARN_ON_ONCE if you don't provide any arch specific idle functions. If >> you wish to allow this case then the correct patch (keeping the WARN_ON) >> would appear to be this one. >> >> James >> >> ---- >> diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c >> index 8b86c0c..829e41f 100644 >> --- a/kernel/cpu/idle.c >> +++ b/kernel/cpu/idle.c >> @@ -56,6 +56,7 @@ void __weak arch_cpu_idle_dead(void) { } >> void __weak arch_cpu_idle(void) >> { >> cpu_idle_force_poll = 1; >> + local_irq_enable(); >> } >> >> /* >> > > This patch looks like the correct fix to me. > > Reviewed-by: Srivatsa S. Bhat Thanks Srivatsa! I can push it through the parisc tree if nobody objects... Helge