From 1380335fc4c60decaee63e6c462267b0e134bd15 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 16 May 2014 11:50:42 +0800 Subject: [PATCH] sched: Fix hotplug vs. set_cpus_allowed_ptr() commit 6acbfb96976fc3350e30d964acb1dbbdf876d55e upstream. Lai found that: WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b() ... migration_cpu_stop+0x1d/0x22 was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is always a sub-set of cpu_online_mask. This isn't true since 5fbd036b552f ("sched: Cleanup cpu_active madness"). So set active and online at the same time to avoid this particular problem. Fixes: 5fbd036b552f ("sched: Cleanup cpu_active madness") Signed-off-by: Lai Jiangshan Signed-off-by: Peter Zijlstra Cc: Andrew Morton Cc: Gautham R. Shenoy Cc: Linus Torvalds Cc: Michael wang Cc: Paul Gortmaker Cc: Rafael J. Wysocki Cc: Srivatsa S. Bhat Cc: Toshi Kani Link: http://lkml.kernel.org/r/53758B12.8060609@cn.fujitsu.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/cpu.c | 6 ++++-- kernel/sched/core.c | 1 - 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index deff2e6..9a1ba77 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -692,10 +692,12 @@ void set_cpu_present(unsigned int cpu, bool present) void set_cpu_online(unsigned int cpu, bool online) { - if (online) + if (online) { cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); - else + cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); + } else { cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); + } } void set_cpu_active(unsigned int cpu, bool active) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 823c9d7..9a8a1fc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5075,7 +5075,6 @@ static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { switch (action & ~CPU_TASKS_FROZEN) { - case CPU_STARTING: case CPU_DOWN_FAILED: set_cpu_active((long)hcpu, true); return NOTIFY_OK; -- 2.7.4