ARM: CPU hotplug: ensure correct ordering of unplug

Don't call idle_task_exit() with interrupts disabled, and ensure
that we have a memory barrier after interrupts are disabled but
before signalling that this CPU has shut down.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 8c81ff9b3732..1a1c5e2b3ef9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -269,9 +269,11 @@ void __ref cpu_die(void)
 {
         unsigned int cpu = smp_processor_id();
 
-        local_irq_disable();
         idle_task_exit();
 
+        local_irq_disable();
+        mb();
+
         /* Tell __cpu_die() that this CPU is now safe to dispose of */
         complete(&cpu_died);