From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759404Ab2GLWgY (ORCPT ); Thu, 12 Jul 2012 18:36:24 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:54985 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759392Ab2GLWgT (ORCPT ); Thu, 12 Jul 2012 18:36:19 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Anton Blanchard , Benjamin Herrenschmidt Subject: [ 014/187] powerpc/xmon: Use cpumask iterator to avoid warning Date: Thu, 12 Jul 2012 15:32:50 -0700 Message-Id: <20120712191523.579620712@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Anton Blanchard commit bc1d7702910c7c7e88eb60b58429dbfe293683ce upstream. We have a bug report where the kernel hits a warning in the cpumask code: WARNING: at include/linux/cpumask.h:107 Which is: WARN_ON_ONCE(cpu >= nr_cpumask_bits); The backtrace is: cpu_cmd cmds xmon_core xmon die xmon is iterating through 0 to NR_CPUS. I'm not sure why we are still open coding this but iterating above nr_cpu_ids is definitely a bug. This patch iterates through all possible cpus, in case we issue a system reset and CPUs in an offline state call in. Perhaps the old code was trying to handle CPUs that were in the partition but were never started (eg kexec into a kernel with an nr_cpus= boot option). They are going to die way before we get into xmon since we haven't set any kernel state up for them. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/xmon/xmon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -971,7 +971,7 @@ static int cpu_cmd(void) /* print cpus waiting or in xmon */ printf("cpus stopped:"); count = 0; - for (cpu = 0; cpu < NR_CPUS; ++cpu) { + for_each_possible_cpu(cpu) { if (cpumask_test_cpu(cpu, &cpus_in_xmon)) { if (count == 0) printf(" %x", cpu);