1 files changed, 10 insertions, 0 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index a1ac7ea245d7..033603c1d7c3 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -301,6 +301,16 @@ int __ref cpu_down(unsigned int cpu)
 
         cpu_clear(cpu, cpu_active_map);
 
+        /*
+         * Make sure the all cpus did the reschedule and are not
+         * using stale version of the cpu_active_map.
+         * This is not strictly necessary becuase stop_machine()
+         * that we run down the line already provides the required
+         * synchronization. But it's really a side effect and we do not
+         * want to depend on the innards of the stop_machine here.
+         */
+        synchronize_sched();
+
         err = _cpu_down(cpu, 0);
 
         if (cpu_online(cpu))