From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 29 Jun 2012 15:28:57 +1000 From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org Subject: [PATCH] powerpc: Use cpumask iterator to avoid warning in xmon Message-ID: <20120629152857.41ac747d@kryten> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 0f3ab06..eab3492 100644 --- 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);