[GIT pull] smp/hotplug fix for 4.14

[Thomas Gleixner]

Linus,

please pull the latest smp-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
smp-urgent-for-linus

The recent rework of the callback invocation missed to cleanup the
leftovers of the operation, so under certain circumstances a subsequent CPU
hotplug operation accesses stale data and crashes. Clean it up.

Thanks,

        tglx

------------------>
Thomas Gleixner (1):
      cpu/hotplug: Reset node state after operation


 kernel/cpu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index d851df22f5c5..04892a82f6ac 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -632,6 +632,11 @@ cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, 
bool bringup,
                __cpuhp_kick_ap(st);
        }
 
+       /*
+        * Clean up the leftovers so the next hotplug operation wont use stale
+        * data.
+        */
+       st->node = st->last = NULL;
        return ret;
 }