[PATCH] cpu hotplug/x86_64: disable interrupt in play_dead

With physical CPU hotplug, the CPU is hot removed and it should not receive
any interrupts.  Disabling interrupt is much safer.  This basically is what we
do in ia64 & x86.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 7519fc520eb3..3060ed97b755 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait);
 DECLARE_PER_CPU(int, cpu_state);
 
 #include <asm/nmi.h>
-/* We don't actually take CPU down, just spin without interrupts. */
+/* We halt the CPU with physical CPU hotplug */
 static inline void play_dead(void)
 {
         idle_task_exit();
@@ -166,8 +166,9 @@ static inline void play_dead(void)
         /* Ack it */
         __get_cpu_var(cpu_state) = CPU_DEAD;
 
+        local_irq_disable();
         while (1)
-                safe_halt();
+                halt();
 }
 #else
 static inline void play_dead(void)