Commit-ID:  b961b5eea6f90e269bfdec7cd0dac98b008ae817
Gitweb:     http://git.kernel.org/tip/b961b5eea6f90e269bfdec7cd0dac98b008ae817
Author:     Lai Jiangshan <la...@cn.fujitsu.com>
AuthorDate: Fri, 16 May 2014 11:50:42 +0800
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Mon, 19 May 2014 21:47:34 +0900

sched: Fix hotplug vs set_cpus_allowed_ptr()

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 <la...@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <pet...@infradead.org>
Link: http://lkml.kernel.org/r/53758b12.8060...@cn.fujitsu.com
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 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 a9e710e..247979a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -726,10 +726,12 @@ 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 44e00ab..86f3890 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5076,7 +5076,6 @@ 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;
--
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